WASHINGTON — (CNN) Hillary Clinton’s methodical search for a running mate is nearly complete, several Democrats close to the vice presidential process say, and she is planning to introduce her new political partner during a campaign rally in Miami on Saturday.

Clinton has yet to reveal her choice to her campaign, and top advisers insist she hasn’t made a final conclusion, fearful of it leaking before a well-orchestrated weekend rollout is set into motion.

But several longtime confidantes familiar with how she makes decisions say that by now, she has almost certainly settled on a candidate to join the Democratic ticket.

The focus of her search in the final days centers on Sen. Tim Kaine of Virginia and Agriculture Secretary Tom Vilsack, according to several Democrats close to the process, confident either contender would fit her chief criteria of being a strong governing partner and ready for the presidency.

She had not formally ruled out Labor Secretary Tom Perez, who would be the first Hispanic candidate on the party’s ticket, or Sen. Cory Booker of New Jersey, who would be the first black vice presidential nominee.

Democrats close to the process said Perez and Booker had considerable strengths, far beyond their diversity, but their limited experience in national security and government made them less likely to be selected.

“She’s not going to be waffling at the 11th hour like (Donald) Trump,” one Democrat close to the process said, speaking on condition of anonymity because of the secrecy surrounding the selection. “By now, she knows who she wants and will be confident in her choice.”

Yet the Clinton campaign is watching the closing day of the Republican convention with great interest, particularly how Trump’s speech is received, which could influence the timing of their own announcement.

The campaign has discussed several scenarios, taking into account the Republican convention as well as a domestic or international outbreak of violence.

The most likely plan calls for Clinton to reveal her decision in a text message to supporters late Friday before appearing with her running mate Saturday at Florida International University in Miami, where the student body is more than half Hispanic.

Kaine speaks fluent Spanish, and last week, Clinton beamed at a Virginia rally as he declared: “Estamos listos para Hillary!” or “We are ready for Hillary!”

The Clinton campaign, looking to build their email and text list, has offered supporters the chance to be the “first to know” their vice presidential pick, much like Barack Obama’s campaign did in 2008.

But a second plan calls for an accelerated announcement — should it leak early, by design or not — with their first joint appearance scheduled for late Friday at the Florida State Fairgrounds in Tampa, where Clinton is also scheduled to hold a campaign rally.

The consensus, even among several Democrats close to other finalists, is that Kaine will be tapped as Clinton’s vice presidential candidate.

Yet other Democrats close to Clinton still cautioned in interviews Thursday against counting out Vilsack, who has the most state and federal governing experience and the longest personal relationship with Clinton.

Neither Vilsack nor Kaine have been informed of Clinton’s decision, people familiar with the process said. Vilsack, visiting Missouri on Thursday to discuss prescription drug addiction, declined to talk about the vice presidential selection. In Virginia, Kaine also brushed aside questions, adding: “It’s kind of surreal.”

Booker, who often fires up audiences for Clinton, appeared with other Democrats in Cleveland on Thursday to push back against Trump and Republicans, who have spent the week assailing her character.

“I don’t know who the nominee is,” Booker told CNN’s Jake Tapper Thursday. “The good thing about it is she has tremendous choices.”

For her part, Clinton has intentionally not informed anyone who has gone through the vetting process of her final decision, Democrats close to the process said, in hopes of keeping her choice a secret until the last possible moment.

But two Democrats close to Sen. Elizabeth Warren of Massachusetts and one close to Sen. Sherrod Brown of Ohio, both of whom were on Clinton’s list of contenders, said Thursday they were all but certain they had not been selected.

All the finalists have met with Clinton at different times, Democrats close to the process say, including Perez, Booker and Warren during one-on-one meetings Friday at Clinton’s home in Washington.

But this week, the Clinton campaign had a meeting with top Warren aides, trying to work out a surrogate schedule for her for the rest of the summer and fall, leading Warren’s team to believe she had not been chosen.

“They have crossed us off the list,” one Democrat close to Warren said.

The selection of either Brown, Warren or Booker would influence the balance of power in the Senate.

Their replacement would be named, at least initially, by a Republican governor in their state, and Clinton is intent on trying to win a Democratic majority in the Senate.

Clinton started this process before her primary fight with Bernie Sanders ended with what aides described as a “fluid” list, including several potential running mates.

Several were eliminated, including Colorado Gov. John Hickenlooper, Housing and Urban Development Secretary Julian Castro and James Stravidis, the former supreme allied commander of NATO and a retired four-star Navy admiral.

She also met with Hickenlooper, Castro and Perez on Friday in Washington.

For Clinton, the selection of a running mate opens a new and important chapter in her political life.

Her first presidential campaign ended long before any serious consideration of a running mate began, so this phase of her campaign is uncharted terrain.

She was deeply involved in the selection of Al Gore to be her husband’s running mate in 1992, but this choice is hers.

Her husband favors Kaine, people close to him say, but one added this week: “He gets a say, but doesn’t have a vote on this.”

The weekend debut of the Democratic ticket is designed to build anticipation for the party’s convention starting Monday in Philadelphia.

After they are formally nominated, Clinton and her new running mate are expected to embark on a bus tour to key campaign battlegrounds, similar to the “First 1,000 Miles” caravan in 1992 that took the Clintons and Gores to eight states on their way to winning the White House in November.