Columnist

Ohio Gov. John Kasich, left, with his wife, Karen, during a speech at the Rock and Roll Hall of Fame and Museum in Cleveland on July 19. (Alex Brandon/Associated Press)

CLEVELAND — The Republican Party must reject all of the fundamental ideas and values that underpin Donald Trump’s foreign policy, Ohio Gov. John Kasich said Tuesday afternoon in Cleveland.

Although he didn’t actually name Trump, Kasich’s comments were the clearest and most comprehensive rebuke of Trump’s foreign policy that any Republican has made here in Cleveland. Most of the Republican leaders speaking at the convention have decided to whitewash or water down their criticism of Trump’s national security ideas in an effort to project party unity.

But Kasich, who is not speaking at the convention in his own state, criticized Trump’s foreign policy ideas one by one and called on the GOP to move in the opposite direction for the sake of the United States and the world.

“So we see in the world growing nationalism, growing isolationism, anti-immigration and anti-trade. Now, if you put all that together, what does that stew look like? What does it mean for the world? What does it mean for stability? What does it mean for relationships?” Kasich said at an event put on by the International Republican Institute. “I’m very worried about it. I’m very, very concerned.”

Kasich said that nationalism becomes a problem when it becomes too inward-looking and too extreme. He said anti-immigration sentiment was “not healthy” and that Ohio, for one, needs and welcomes immigration as part of its growth strategy. He attacked the presumptive nominee’s call for the United States to reduce its role in NATO and let European allies take over more of their own security.

“We think NATO doesn’t matter? Are we kidding?” Kasich said.

Kasich’s most impassioned indirect attack was directed at Trump’s views on Russia, Ukraine and Vladimir Putin. He criticized the idea that the United States should disregard Russian bad behavior and work with Russia more.

He referenced my Monday report about how the Trump campaign worked behind the scenes last week to remove language in the GOP platform that would have called for “lethal defensive weapons” for Ukraine. The Trump staff weakened that language to “appropriate assistance.”

“As long as I’m breathing air, I’m for arming the Ukrainians who want to fight for freedom,” said Kasich. “So it must have been a terrible mistake that apparently arming the Ukraine was somehow left out of the Republican platform.”

The United States should push back against Russian aggression and not play into Putin’s strategy to weaken relationships between the United States and European countries, according to Kasich. He also said Brexit was bad for the United States because Britain’s voice in European security affairs would now be weakened.

“Who was the happiest man in the world with the Brexit? Vladimir Putin!” he said. “I’m concerned about Russian aggression.”

The Kasich and Trump teams have been trading barbs about Russia and Ukraine all week. On Monday, Kasich’s former campaign manager John Weaver referenced on Twitter the fact that Trump campaign chairman Paul Manafort lobbied for the Russian-backed former president of Ukraine, Viktor Yanukovych.

Lastly, Kasich defended the Trans-Pacific Partnership and free trade deals in general, the last in a long line of criticisms of the foreign policy planks Trump has based his campaign on.

“Trade is not only an economic issue, but when I look at TPP, I don’t think we can afford to walk away from all our friends in Asia,” he said. “Trade is not just an issue of economics, it’s an issue of global security.”

Sen. Marco Rubio (R-Fla.) was still feigning optimism about Trump’s foreign policy Tuesday afternoon when CNN’s Jake Tapper asked him about Trump’s coziness with Russia. Rubio said he disagreed with Trump but perhaps Trump will evolve if elected president.

“My hope is that when Donald Trump gets there, that he changes his opinion on things based on information that he has access to that he doesn’t have access to now,” said Rubio.

But Trump and his campaign have been very clear that their foreign policy agenda is based on what they truly believe and will not change if he’s elected president. What would change is the fundamental national security stance of the GOP.