Donald Trump's running mate, Gov. Mike Pence, attacked Russian president Vladimir Putin as a "small and bullying leader" during today's vice-presidential debate - a sharp break from Trump's own attitude toward Putin, which has been warm and conciliatory.

"The small and bullying leader of Russia is not dictating terms to the United States," Pence said. "We have got to be able to lean into this with strong, broad-shouldered American leadership."

Pence went on to call for U.S. military strikes against a key Russian military ally, the regime of Syrian leader Bashar Assad, if Assad's regime threatened to move against a besieged rebel enclave around Aleppo, Syria.

"The provocations by Russia need to be met with American strength," Pence said. "The United States of America should be prepared to use military force to strike military targets of the Assad regime."


Sen. Tim Kaine, the running mate of Democrat Hillary Clinton, raised the issue of Trump's praise for Putin.

"If you don't know the difference between dictatorship and leadership, then you've got to go back to a 5th-grade civics class," Kaine said.

After its first hour, the debate between Kaine and Pence was defined by frequent interruptions by Kaine, and - from Pence - a calm, confident disdain, and a constant struggle to reconcile his positions with those of Trump himself. Earlier in the evening, Pence seemed to back away from a key piece of Trump's policy agenda during the Republican primaries, a plan to deport undocumented immigrants en masse.

"In all six cases, he's refused to defend his running mate. . .and yet, he's asking everybody to vote for somebody that he cannot defend," Kaine said at one point.

On immigration, Pence, instead, said that Trump would focus first on ending illegal immigration and deporting "criminal aliens."

"Once we have accomplished all of that. . .Then we'll deal with those that remain," Pence said, while giving no more details. Trump said repeatedly during the GOP primary that he wanted to immediately deport 11 million immigrants already in the United States.

Kaine tried to tie Pence to Trump's past statements, saying that "Donald Trump believes in deportation nation. You've got to pick your choice."

"That's nonsense," Kaine said. "It's nonsense."

In the only vice-presidential debate of the season, moderator Elaine Quijano pressed Pence to say if he would follow through on Trump's previous mass-deportation plan. Pence did not answer directly. Instead, he said he would seek to work with Democrats to work on an undisclosed answer: "Senator, I'll work with you when you go back to the Senate," he said to Kaine.

While Pence seemed to pivot on Trump's immigration priorities, he stuck with Trump's stance on taxes. Pence did not challenge the notion that his running mate had not paid federal income taxes - saying that Trump had used the tax code "brilliantly."

Pence was asked about a New York Times report, which relied on leaked pages from Trump's 1995 tax returns, which showed that Trump had claimed a $916 million loss - and might have been able to avoid federal income taxes for up to 18 years. Pence did not make any claim that Trump had paid federal income taxes.

"His tax returns showed he went through a very difficult time, but he used the tax code the way it was meant to be used, and he used it brilliantly," Pence said. "Donald Trump has created tens of thousands of jobs, and he's paid payroll taxes, property taxes. . .."

Kaine of Virginia challenged Pence to say why Trump had not released his tax returns, as other nominees have for 40 years. Pence repeated what Trump has said - that he would release the tax returns, but only when an IRS audit is over. The IRS has said that there is no legal prohibition on releasing taxes while they are under audit.

The two candidates spent the debate's first half-hour using sharply different strategies: Kaine was aggressive, interrupting and hurling pre-rehearsed insults at Pence. Pence was calmer, counter-punching with an edge of disdain for Kaine's tactics.

"People at home cannot understand either one of you when you speak over each other," moderator Quijano said at one point, frustrated that the two men would not let one another talk.

Earlier, Kaine opened the debate by saying he was "scared" of the prospect that the GOP nominee would become president, while his son is serving in the Marine Corps.

"We trust Hillary Clinton as president and commander-in-chief," Kaine said, speaking of himself and his wife. "The thought of Donald Trump as commander-in-chief scares us to death."

Kaine began the debate, held in Farmville, Virginia, on the attack. He turned two of the first answers from questions about himself or Clinton into attacks on Trump.

"I can't imagine how Gov. Pence can defend the insult-driven, selfish, me-first style of Donald Trump," Kaine said.

The debate, which pitted two nominees with vanilla reputations, turned quickly bitter, with both Kaine and Pence interrupting each other.

"Senator, you and Hillary Clinton would know a lot about an insult-driven campaign. It really is remarkable," Pence said.

After being interrupted by Kaine again, Pence responded in a flat tone that belied the bitter tone of the debate. "I musta hit a nerve here,"he said.

"You are Donald Trump's apprentice," Kaine said at one point, implying that the famously genial Pence had taken on Trump's aggressive persona.

It seemed clear that Kaine had come armed with pre-planned zingers that mocked Trump, with varying degrees of zing.

"Do you want a 'You're hired' president under Hillary Clinton, or do you want a 'You're fired' president, under Donald Trump," Kaine said.

Pence mocked that: "You used that a lot, and I think your running mate used a lot of pre-planned lines."

The debate began a few minutes after 9 p.m. at Longwood University. It is the only vice-presidential debate of the 2016 election, and it comes at a moment when the Democratic ticket, led by Clinton, seems to be pulling away.

For the two men, this is the biggest night of their political lives. But, if they do their jobs right, they will shift the focus elsewhere, onto the two candidates at the top of their respective tickets.

Pence and Kaine are dueling over the temperament, qualifications, honesty and records of Trump and Clinton, as the two affable and smooth-talking men explain and proselytize for their historically unpopular running mates.

The Clinton campaign hinted at Kaine's strategy in a tweet Tuesday morning that read: "Imagine Donald Trump's most hateful rhetoric signed into law. Mike Pence's record shows that it could happen."

The campaign posted examples on its website of ideas that Trump has floated - such as ending birthright citizenship, restricting access to abortion, lessening gun restrictions and making it more difficult to vote - along with similar legislative action that Pence has taken or supported. The campaign also released a video titled "The Same" that compared comments from Trump and Pence on gay rights, global warming, the minimum wage and other topics.

Kaine himself tweeted a "message to Donald Trump and Mike Pence" on Tuesday morning: "We're going forward, not backward," written in both Spanish and English.