President Donald Trump on Thursday announced tariffs on polysilicon and its related products, in his administration’s latest attempt to eliminate China’s choke points in the global supply chain for solar panels and semiconductors.

But Trump’s directive won’t take effect until Dec. 4 — well after November’s midterm elections and a planned September summit between Trump and Chinese leader Xi Jinping — as the administration grapples with voters complaining of high prices and fragile trade negotiations with China.

“This will bring the supply chain here,” Commerce Secretary Howard Lutnick said of the order on Thursday alongside Trump at the White House. “We’ve got the industry here, it’s too small, and it’s going to explode.”

Because polysilicon is used in semiconductors and solar panels, it’s essential for military hardware and everyday electronics like cell phones and laptops, in addition to the world’s fastest-growing energy source.

The order imposes a 15 percent tariff on imported polysilicon and its derivatives, as well as minimum prices for imports of polysilicon, polysilicon ingots and wafers, solar cells and solar modules.

It also includes a clause intended to prevent companies from stockpiling those materials between now and December, authorizing Customs and Border Protection to restrict imports if it suspects an importer is attempting to dodge the higher duties.

Trump’s order is the result of a Commerce Department investigation launched last July into national security risks in the polysilicon supply chain, as part of a broader effort to shift supply chains away from China for multiple industries including wind turbines and robotics.

China has a near-monopoly on the production of polysilicon, according to S&P Global. But recent U.S. efforts to limit key areas of trade with China have already drawn a backlash from Beijing, which earlier this week implemented new controls on drone exports to the U.S.

The White House emphasized the order’s impact on domestic semiconductor production, a key focus as the U.S. looks to build out infrastructure related to artificial intelligence. Trump said the U.S. will “have a big percentage of the chip business by the time I leave office.”

But Thursday’s order may have a big impact on the solar industry, according to Jon Toomey, president of the pro-tariff Coalition for a Prosperous America organization.

“This proclamation delivers the most significant global trade protection action for the American polysilicon and solar industry in the modern era,” Toomey said in a statement. “For the first time, the United States is protecting the entire solar supply chain with a single action — and rewarding the manufacturers that build here — while taking a significant step to bolster the domestic semiconductor supply chain.”

A group of 25 Democratic-led states sued President Donald Trump’s administration Monday to block the latest round of tariffs imposed on goods from dozens of countries.

The lawsuit in the U.S. Court of International Trade marks the latest in a growing list of legal actions that accuse the White House of exceeding its authority when it used Section 301 of the Trade Act of 1974 — which allows a president to impose tariffs over unfair trade practices — to penalize countries over the alleged use of forced labor after prior trade penalties had either expired or been invalidated by the Supreme Court.

“The Plaintiff States oppose forced labor in all its forms and support protections for workers around the globe,” the states said in their lawsuit. “But the Administration cannot use forced labor as a pretext to continue its illegal tariff scheme.”

Monday’s complaint contests tariffs of 10 or 12.5 percent the administration slapped on goods from 60 economies, including China and the European Union, that took effect last month.

“President Trump is so intent on raising the cost of living for Americans that he is willing to break law after law after law to do so,” said California Attorney General Rob Bonta, whose state is among the plaintiffs, in a statement announcing the lawsuit.

“Tariffs are taxes,” Bonta said. “And the American people cannot and should not shoulder the extra costs that come from the President’s failed and illegal economic policy — no matter how much the President wants them to.”

The effort to block Trump’s third crack at rebuilding his global tariff regime comes after the Supreme Court in February knocked down tariffs the president imposed on countries under the 1977 International Emergency Economic Powers Act, and after the Court of International Trade ruled in May that the Section 122 surcharge Trump imposed in their place was also illegal. The trade court’s May ruling was stayed, allowing the duties to keep being collected pending appeal. Those tariffs expired last month.

The White House defended the tariffs, saying the administration was using its “lawful authority” to crack down on practices that burden American commerce.

“A foreign country’s failure to impose and effectively enforce a prohibition on the importation of goods produced with forced labor is unreasonable and burdens U.S. commerce, including American workers, and must be addressed,” White House spokesperson Kush Desai said in a statement. “Section 301 tariffs have proven to be a legally durable tool since the President’s first term, and they remain so now.”

The lawsuit also accuses the U.S. of bypassing country-specific consultations and failing to explain why duties on countries with such varied forced-labor measures were set in a “nearly uniform manner.”

And it comes on the heels of lawsuits from two groups of small businesses that challenged the tariffs the day they took effect: one led by Burlap & Barrel, a New York spice importer, and a separate suit led by Learning Resources, an educational-products maker that was the named plaintiff in the Supreme Court case that invalidated Trump’s IEEPA tariffs.

Background: The dispute centers on Trump’s use of Section 301, an authority widely viewed as far more legally durable than the other powers Trump tapped to impose tariffs.

Duties from one Section 301 investigation into China during Trump’s first term have now lasted more than seven years. But Section 301’s durability does not give the president unlimited discretion, because the law requires the USTR to identify specific foreign acts, policies or practices and show that they burden or restrict U.S. commerce.

Matthew Seligman, founder of Grayhawk Law and an attorney representing importers seeking tariff refunds, said the states’ challenge is strong but faces a harder legal path than the challenges to the IEEPA and Section 122 tariffs.

“Unlike those prior cases, this case will turn on how much the courts defer to the administration’s seemingly pretextual rationalization that these tariffs are aimed at combatting forced labor,” Seligman said.

“Typically, courts grant substantial deference to the executive branch about these sorts of policy judgments — especially when it implicates foreign affairs —but, as is so often the case with the Trump administration, this case will really test the limits of that judicial deference,” he added.

Washington is again ratcheting up the pressure on the European Union with new tariff threats. Brussels’ response is strikingly different from a year ago: Don’t retaliate, don’t put on a show for Donald Trump, and don’t let him dictate the timetable.

Trump’s recent threat to “immediately initiate” a trade investigation over the European Commission’s $1 billion fine against Google came on top of new tariffs on the EU and dozens of other trading partners, and continuing pressure from Washington over drug pricing.

But rather than sounding alarms and scrambling to respond to this new phase of Trump’s global trade war, the EU has shown public restraint — a reaction that suggests that the 27-member bloc has become less susceptible to Trump’s pressure tactics.

This year, European capitals saw their united rejection of Trump’s Greenland ambitions fail to trigger a wider transatlantic rupture. His most sweeping tariffs were struck down by the Supreme Court, and their successors have drawn legal challenges. Now, with a chance that Trump’s grip on Washington loosens in the November midterm elections, Europeans are happy to play for time.

“It is a strategy of buying time through dialogue,” Bernd Lange, a German member of the European Parliament and chair of its Committee on International Trade, said in an interview. “The Commission’s approach is to move away from anything that could be seen as legally binding and focus instead on dialogue forums, consultation and areas where cooperation is possible.”

Last year, Brussels repeatedly bristled at Trump’s tariff threats, which at times reached as high as 50 percent, before agreeing to a trade truce at the U.S. president’s golf resort in Turnberry, Scotland. After months of delays that tested Washington’s patience, the EU fulfilled its side of the bargain by passing legislation in June to allow U.S. industrial and some agricultural goods to enter the bloc duty-free.

A USTR official, granted anonymity to share the administration’s thinking, credited the EU for implementing “key commitments,” in the Turnberry deal, “such as massive tariff reductions for U.S. exports, and has made concrete commitments on a number of other burdensome regulatory matters.”

“Any technical talks will be about implementing the remaining commitments, and the U.S. side anticipates this will move at pace,” the official added.

The White House did not respond to a request for comment.

The EU law, however, also includes guardrails should Trump threaten the bloc again.

It didn’t take long for him to do so.

While the 10 percent tariff the U.S. government rolled out July 23 does not violate the Turnberry agreement, which caps U.S. duties on most EU goods at 15 percent, Trump’s threats to investigate Europe’s digital restrictions in the wake of the Google fine would likely do so. The Office of the U.S. Trade Representative has yet to launch an official investigation, but the official there confirmed to POLITICO that the agency expected “to initiate the investigation soon”. That could allow the White House to layer on more tariffs on EU imports.

U.S. Trade Representative Jamieson Greer is also conducting a separate trade investigation into Germany’s pharmaceutical pricing and has suggested he could launch similar reviews of other European countries’ drug pricing practices as well.

Those investigations, however, will take months to resolve, if not longer.

“The second phase of the trade war touches a nerve in Europe: sovereignty. Whether it concerns taxation, health care systems or competition policy, these are areas the EU sees as core to its autonomy,” said Jeromin Zettelmeyer, a former International Monetary Fund and German government official who now heads Brussels-based think tank Bruegel.

“At the same time, Trump no longer appears as politically untouchable as he did at the start of his presidency. Weakening poll numbers ahead of the midterms, controversy over the Iran war and legal setbacks in the U.S. Supreme Court have exposed vulnerabilities,” Zettelmeyer said.

In the meantime, EU officials are keeping channels to Washington open. The thinking in Brussels is that every public confrontation plays to Trump’s preferred negotiating style, whereas slower legal and technical processes give the EU more room to manage disputes on its own terms.

Nor is German Chancellor Friedrich Merz in a rush to offer concessions to the Trump administration on drug pricing, according to a European official familiar with the issue who was granted anonymity to discuss the sensitive talks. Berlin expects the U.S. trade investigation to take at least a year, the person noted.

Brussels is in close touch with Berlin on the probe, which it believes could be a blueprint for other possible U.S. trade investigations into France and Italy’s pharmaceutical policies. Ditte Juul Jørgensen, head of the Commission’s trade department, recently met with German officials in Berlin to focus on a way forward on drug pricing.

The Commission has adopted a similar strategy on transatlantic disagreements on digital policy.

While the Trump administration has pressed for broader talks, including on the enforcement of the EU’s competition rules governing Big Tech platforms, Brussels has taken pains to keep the discussions at a technical level.

In early July, a group of officials from the European Commission’s trade and tech departments headed to Washington for what a Commission spokesperson described as “a dialogue on the dialogue.”

A senior Commission official said the meeting was about seeing where the two sides could “partner up,” with Brussels looking at holding a “high-level” meeting with Washington in the fall and a series of technical rounds in between.

“From the EU’s perspective, both sort of genetically as an organization and tactically, they would be happy if as many of the discussions as possible moved to the technical level in dialogue committees rather than have it be, like, Donald Trump and somebody going at it on Twitter or in competing press statements,” said Dmitry Grozoubinski, a former trade diplomat for the Australian government and the founder of ExplainTrade, an outlet based in Geneva.

The Commission responded with characteristic restraint after Trump threatened retaliation over the latest Google fine. After the U.S. president’s Truth Social post, Brussels emphasized it would seek “technical-level contact” between the EU and the U.S., said deputy chief spokesperson Olof Gill. A meeting at a higher, political level hasn’t yet been confirmed.

However, several people familiar with the matter confirmed they were expecting a reaction from the U.S., possibly in the form of a new 301 investigation.

“I have not heard anything yet on timing for the launch or scope of the Section 301 investigation,” said a U.S. tech industry representative, who was granted anonymity to discuss the conversations with administration officials. “But I believe this has been in the works for some time as a means of leverage in U.S. negotiations with the EU.”

Europe’s strategy depends on shifting disputes out of Trump’s preferred arena of public confrontation. But officials acknowledge that this bet rests on one unpredictable factor: Trump himself.

“We cannot let our guard down,” another Commission official said. “Trump may change course at any moment. His focus is on how markets react to his policies, not on how the EU behaves.”

Stefanie Bolzen reported from Washington and Camille Gijs reported from Brussels. Oliver Ward contributed to this report.