Sources: Kaine emerges as favorite in Clinton's VP search

STERLING, Virginia -- Virginia Sen. Tim Kaine has emerged as the leading contender to join the Democratic ticket as Hillary Clinton's running mate, according to two Democrats, who cautioned Clinton has not made a final decision and could change directions.

The announcement of Clinton's pick could come as early as this afternoon in Florida, a crucial general-election battleground state.

The timing is aimed at shifting attention away from the end of Donald Trump's Republican convention and generating excitement before the start of Clinton's own convention next week in Philadelphia.

Kaine, 58, has been a favorite for the vice-presidential slot since the start of Clinton's search process. He has been active in the Senate on foreign relations and military affairs and built a reputation for working across the aisle as Virginia's governor and mayor of Richmond.

"I'm glad the waiting game is nearly over," Kaine told reporters Thursday after an event in northern Virginia, deflecting questions about whether he was about to join the ticket.

Agriculture Secretary Tom Vilsack, a longtime friend of Hillary and Bill Clinton, is still in the mix, according to one of the two Democrats, who is close to the Clintons. Both Democrats are familiar with the selection process and spoke on the condition of anonymity because they were not authorized to discuss it publicly.

Clinton's campaign declined to comment.

Kaine's selection would not be without complication. Liberals have expressed wariness of Kaine for his support of putting the Trans-Pacific Partnership trade agreement on a "fast track" to approval, which Clinton and primary rival Bernie Sanders oppose. They also note Kaine recently signed onto a letter asking for less burdensome regulation of regional banks.

But President Barack Obama has told the campaign he believes Kaine would be a strong choice, according to a Democrat familiar with the search who was not authorized to discuss it publicly.

If Kaine were selected for the ticket, Virginia Gov. Terry McAuliffe, a Democrat and ally of the Clintons, would choose a temporary replacement, but the race for the remainder of Kaine's term would take place in 2017, raising the possibility Republicans could win the seat.

He was scheduled to attend fundraisers today and Saturday in Massachusetts.

Vilsack is the longest-serving member of Obama's Cabinet and has known Clinton for years. He first met her through his late brother-in-law, who worked with Clinton on the Watergate Committee in 1972, and she campaigned for Vilsack in 1998 during his surprise victory as Iowa governor.

If he were added to the ticket, Vilsack could help Clinton in Iowa and connect with rural America.