Donald Trump has one policy toward Russia. His vice-presidential nominee, Mike Pence, seems to have another.

At least, that was the case during Tuesday’s vice-presidential debate.

While Trump has repeatedly praised Russian President Vladimir Putin—and, at times, pushed a foreign-policy agenda that sounds like it came straight out of the Kremlin—during Tuesday’s vice-presidential debate, Pence refused to adopt Trump’s embrace of Putin. Rather, he said the U.S. would meet Russian aggression with “strength.”

Then he called Putin a “small and bullying leader.”

In August, Trump was pushing an alliance with Russia to stop ISIS in Syria. On Tuesday, Pence suggested the U.S. should be prepared to deploy its military to stop Russian aggression there. Russian airstrikes on behalf of Syrian President Bashar al-Assad, which began Sept. 30, have allowed the regime to not only survive the five-year civil war, but in recent weeks, fight to wrest parts of Syria’s largest city, Aleppo, from opposition control.

“The United States of America should be prepared to use military force to strike military targets of the Assad regime,” Pence said.

Pence’s unwillingness to defend a keystone of Trump’s foreign policy was a notable break in the platform Tuesday, which some watchers interpreted as a politician eyeing the 2020 election, not the one slated for next month.

It was a change in Pence’s position from just a few weeks ago when Pence said, “It’s inarguable that Vladimir Putin has been a stronger leader in his country than Barack Obama has been in this country.” Trump also has repeatedly called Putin a better leader than Obama.

But during the debate, Pence promised a stronger response to Russian aggressions in Syria and condemned Russia aggression into Ukraine.

“I mean, the situation we’re watching hour by hour in Syria today is the result of the failed foreign policy and the weak foreign policy that Hillary Clinton helped lead in this administration and create. The newly emboldened—the aggression of Russia, whether it was in Ukraine or now they’re heavy-handed approach…,” Pence said.

“You guys love Russia,” an apparently surprised Tim Kaine, the Democratic vice-presidential candidate responded.

“Heavy-handed,” Pence interjected.

Pence also criticized the Obama administration’s failed attempt to reset relations with Russia even as Trump has repeatedly called for a reset of sorts, improving relations with Putin.

Pence’s campaign performance reflected an apparent tension between the two candidates at the top of the Republican ticket.

Pence has walked back his praise of Putin last month, saying he doesn’t “doesn’t particularly like the system” of governance operating under Putin.

And even during the debate, On Tuesday, Pence noted that his praise of Putin “is not an endorsement of Vladimir Putin. That is an indictment of the weak leadership of Hillary Clinton and Barack Obama.”

Meanwhile, Trump, at one point, suggested the Russians hack into the U.S. to retrieve Democratic nominee Hillary Clinton’s missing emails from her time as secretary of State. (He later walked back the remark, saying it was just a joke.)

And earlier Tuesday, Trump blamed both Russia and the Obama administration for the Sept. 19 collapse of the cease-fire in Syria. Russia, Trump said, “broke the deal” because it doesn’t respect America’s leaders.