Hillary Clinton selects Tim Kaine as running mate

Hillary Clinton has selected Sen. Tim Kaine as her vice presidential running mate.

The Virginia senator is expected to appear with Clinton in Miami for their first joint appearance Saturday.

"I'm thrilled to tell you this first. I've chosen Sen. Tim Kaine as my running mate," Clinton told supporters in a text message.

Clinton's selection of Kaine could help bolster the former secretary of state's chances in Virginia, a key swing state.

Prior to serving as on the Senate Armed Services committee as a Virginia senator, Kaine was the state's governor, the mayor of Richmond, and the chair of the Democratic National Committee.

Still, liberal critics appear less than enthused by Kaine.

Some have dismissed the senator as boring and not adequately progressive on issues like trade. But some criticism of the senator appears more based in his longtime ties to party leadership rather than his actual stances on policy.

Kaine is willing to concede that at least one of those charges may be true.

"They're true. I am boring. But boring is the fastest-growing demographic in this country," Kaine said during an appearance last month on "Meet The Press."

This story will be updated.