Tim Kaine pulled out a trump card against the Republican presidential nominee at his first appearance as presumptive Democratic standard-bearer Hillary Clinton's running mate.
At a Miami rally Saturday, the Virginia senator said one of his sons, who is a U.S. Marine, will soon be deployed to Europe in support of NATO allies, an obvious opening for the generally affable Virginia senator to whack Donald Trump.
"He repeatedly calls the American military, 'a disaster.' And just this week, Donald Trump said that as president, he'd consider turning America's back on our decades-old commitments to our allies," Kaine said. "While our service members are out there on the front lines, Trump's saying he'd leave our allies at the mercy of an increasingly aggressive Russia. And folks, that's an open invitation for Vladimir Putin to just roll on in."
"We've seen again and again that when Donald Trump says he has your back, you better watch out," he said.
It was the genial Kaine assuming the classic role of the vice presidential candidate as lead attack dog.
Clinton and Kaine emerged on the Miami stage with their arms raised. Then sitting behind her, he grinned ear-to-ear as she introduced him.
"Make no mistake, behind that smile, Tim also has a backbone of steel. Just ask the NRA," Clinton said, referring to Kaine's history of battling with the gun rights organization.
Much of the talk from Clinton and Kaine to a packed house was about introducing Kaine to audiences unfamiliar with him and outlining what a Clinton-Kaine administration wants to accomplish. Kaine delivered parts of his speech in Spanish.
The pair aims to build on an already solid Democratic Latino demographic with a record 27.3 million Hispanics eligible to vote this year, according to the Pew Research Center. Immigration again is a hot-button issue.
Florida also is crucial for Clinton with the race tightening even more there and in other battleground states after the Republican convention.
Kaine said that within the first 100 days, Clinton would propose an overhaul of immigration laws, including a pathway to citizenship for the approximately 11 million undocumented immigrants in the country today. He also highlighted economic priorities for Democrats, like an increased minimum wage.
Clinton's introduction of Kaine focused chiefly on the new addition to the ticket.
Both Clinton and Kaine recounted his resume — as a civil rights attorney, Richmond mayor, Virginia governor and U.S. senator — to stress a shared commitment to public service.
His speech ranged from the folksy, when talking about his upbringing in the Midwest, to the emotional, when describing a visit to Virginia Tech after the mass shooting there in 2007 as the worst day of his life.
And he spent time going after Trump for the business mogul's failure to release tax returns and for what he called the GOP nominee's "Me First" attitude.
"When this election is done, the only thing people will remember about Donald Trump is 'You're fired!'" Kaine said.
Just after Clinton and Kaine finished, another potential vice presidential choice and favorite of the party's liberal wing threw her weight behind the ticket, in a move that could quell some progressive angst about the Kaine selection.
Speaking at a National Council of La Raza event Saturday a few hours drive north in Orlando, Sen. Elizabeth Warren of Massachusetts repeated her call for Democrats to do everything they can to ensure Trump is never elected president.
"We believe that we must make Hillary Clinton the next president of the United States and Tim Kaine the next vice president of the United States," Warren said. "Not can, not should. Must — must make them."