Foreign policy, for Donald Trump, is based largely on a belief that being tougher on America’s allies and more lenient on its foes will produce better results. But the president’s approach rankles both Republican and Democratic members.

“We’re being respected again. We’re being respected abroad,” Trump declared Friday. “And we are restoring our wealth at home. It’s about time.”

That rosy assessment of his first 16 months in office has become a staple of his public remarks. The Friday declaration came one day after Trump ordered tariffs on steel and aluminum imported from countries including the European Union, Canada and Mexico — some of America’s closest allies.

The tariffs announcement caught leaders in Brussels, Ottawa and Mexico City off guard since talks about those governments getting permanent waivers were ongoing. European and North American allies responded by threatening to retaliate. Experts warned of a world on the brink of a trade war.

Lawmakers of various political stripes howled as they continued to come to grips with Trump’s special blend of realist, mercantilist and isolationist foreign policy thinking. For the GOP, Trump’s treatment of the EU, Canada and Mexico is a rare matter on which his fellow Republicans publicly — and often harshly — criticize him.

“I disagree with this decision. … Today’s action targets America’s allies when we should be working with them to address the unfair trading practices of countries like China,” House Speaker Paul D. Ryan said in a statement. “There are better ways to help American workers and consumers.”

Nebraska Republican Sen. Ben Sasse, who has warned the trade war will hurt farmers in states like his, was more blunt, issuing a scathing rebuke of the GOP president.

“This is dumb. Europe, Canada and Mexico are not China, and you don’t treat allies the same way you treat opponents,” he said. “We’ve been down this road before — blanket protectionism is a big part of why America had a Great Depression. ‘Make America Great Again’ shouldn’t mean ‘Make America 1929 Again.’”

Tennessee GOP Sen. Lamar Alexander called the fees on EU, Canadian and Mexican goods a “big mistake.”

Democratic Sen. Patrick Leahy zeroed in on his home state in criticizing the president’s treatment of U.S. friends. “Canada is Vermont’s largest trading partner, and Vermonters stand to lose big under this ham-handed policy,” he said. “The promised EU and Mexican tariffs on U.S. cheese are another example of the reckless harm the president is risking for Vermont and the nation.”

The criticism hasn’t slowed Trump. He lashed out Thursday evening and again Friday morning at America’s northern neighbor — just hours before he hosted a senior North Korean official, Kim Yong Chol, in the Oval Office on Friday afternoon.

[Trump Demands Canada Take Down ‘Trade Barriers’]

He issued a warning to Canadian officials Thursday evening, saying in a statement he believes “the United States has been taken advantage of for many decades on trade.”

“Those days are over,” Trump said. “Earlier today, this message was conveyed to Prime Minister Justin Trudeau of Canada: The United State[s] will agree to a fair deal, or there will be no deal at all.”

The next morning, the president used a tweet to demand the Canadian government “open their markets and take down their trade barriers!” Canadian officials have “treated our Agricultural business and Farmers very poorly for a very long period of time,” he wrote, calling the Canadian government “Highly restrictive on Trade!” He pointed to timber and lumber trade in particular.

Trump and Trudeau have traded barbs over trade for months. In recent weeks, the White House has released chilly — and brief — summaries of phone conversations between the two leaders, who are very different: one is youthful and worldly, the other is in his early 70s and a proud nationalist.

As the president blasted America’s longtime allies over trade, he struck a much different tone toward North Korea. Though just two weeks ago he issued a reminder to the North’s enigmatic leader, Kim Jong Un, about the lethality and size of the U.S. nuclear arms arsenal, Trump has also been much more conciliatory toward the Asian leader with whom he eagerly wants to cut a denuclearization deal.

“I think there’s a lot of goodwill. I think people want to see if we can get the meeting and get something done,” Trump said on May 26. “We can be successful in the denuclearization of the Korean Peninsula. That would be a great thing for North Korea.”

The next day, the U.S. commander in chief tweeted: “I truly believe North Korea has brilliant potential and will be a great economic and financial Nation one day. Kim Jong Un agrees with me on this. It will happen!” He posted on the matter again on May 29, saying: “Kim Young Chol, the Vice Chairman of North Korea, heading now to New York. Solid response to my letter, thank you!”

Our United States team has arrived in North Korea to make arrangements for the Summit between Kim Jong Un and myself. I truly believe North Korea has brilliant potential and will be a great economic and financial Nation one day. Kim Jong Un agrees with me on this. It will happen!

— Donald J. Trump (@realDonaldTrump) May 27, 2018

We have put a great team together for our talks with North Korea. Meetings are currently taking place concerning Summit, and more. Kim Young Chol, the Vice Chairman of North Korea, heading now to New York. Solid response to my letter, thank you!

— Donald J. Trump (@realDonaldTrump) May 29, 2018

Trump sounded even friendlier on Friday as he rekindled hopes for his on-again, off-again June 12 summit with the North Korean leader. “The relationships are building, and that’s a positive thing,” he told reporters on the South Lawn, after announcing the summit will go forward after all. 

Meanwhile, Trump and his top aides have had nothing but criticism and scorn for Washington’s neighbors and oldest friends.

“We told them a while ago, many months ago, that we wanted help on these issues,” Lawrence Kudlow, Trump’s top economic adviser, said Friday of European leaders. “We wanted help, for example, on China’s crusade to subsidize steel production, corner markets, and ship the steel through all kinds of ports … and therefore drive prices down. … They may give it to us yet. It just hasn’t happened yet.”

As lawmakers objected to the president’s cold treatment of U.S. allies, Sue Mi Terry, a former CIA Korea analyst who also worked for the Bush and Obama White Houses on the National Security Council, said the current thaw with North Korea is unprecedented.

“When you look at North Korea’s last statement that came out seven hours after Trump canceling the meeting, that was very conciliatory in tone,” Terry said. “I have not seen a North Korean statement that’s that conciliatory, actually personally praising [a] U.S. president.”

[Trey Gowdy, Once Championed by the Right, Now a Pariah for FBI Defense]

Senior North Korean leaders praised Trump’s “bold decision or Trump-style negotiation, they were looking forward to meeting Trump,” Terry said. “So I think President Trump basically thought, ‘OK, North Koreans are serious about … having this meeting, and so the summit is back on.”

There is reason to believe the transactional Trump will keep up his approach of pressing harder for concessions from allies while dangling carrots for foes.

Kudlow on Friday cautioned against expecting a quick solution to the administration’s trade tiffs. “This is a story that’s going to play out for a while,” Kudlow said. “I say, ‘Let’s talk.’ And I believe the president is a superior negotiator. So, let’s see where this takes us.”

Near the end of his 10-minute driveway gaggle with reporters, Kudlow offered a prediction that will likely further frustrate Republican and Democratic lawmakers. It was vintage Trump-speak: a bold and rosy pronouncement without an explanation of how to achieve it.

“You’ll have the proverbial rainbow, at the end of which is a pot of gold,” Kudlow said with a grin. “And when you open that pot, we will have faster economic growth.”

With control of the House and Senate — and the fate of the Trump-GOP agenda — on the line in November, Republican lawmakers hope Kudlow delivers some results soon.