Adding to the day's circus atmospherics was the unusually open way two of the finalists discussed the vetting process.
Protocol dictates discretion from anyone being seriously considered. But Gingrich behaved like a contestant on Trump's former reality TV show, "The Apprentice," keeping a high public profile as he awaited word on who would join the GOP ticket.
In a 16-minute video monologue Thursday on his Facebook page, Gingrich said Trump's chief legal vetter, Washington lawyer A.B. Culvahouse, had asked him and his wife, Callista, 113 questions and required more than a decade of tax returns and a list of everything he'd ever written.
"It's a very, very serious, elaborate process," Gingrich said.
Christie acknowledged on MSNBC his hankering for the job, another breach of political protocol.
"I'm not going to say it won't bother me if I'm not selected. Of course it bothers you a little bit," Christie said. "Because if you're a competitive person, like I am, and you're used to winning, like I am, again, you don't like coming in second, ever."
But the risks of picking Christie were underscored Thursday when one of his closest associates, David Samson, pleaded guilty to bribery for abusing his post as a Port Authority chairman.
Pence, 57, is an Indiana native, a lawyer by training and a former talk radio host who served six terms in the House before winning the governorship in 2012.
Reed said Pence also appeals to the governing wing of the party and could use his years in Congress to help Trump navigate Capitol Hill — one of the things the Manhattan businessman has said he wants in a running mate.
Reed Galen, a GOP strategist who worked for former President George W. Bush, said Pence's even demeanor and family-man image would balance Trump's more picaresque personality. "He's the yang to Donald's yin," Galen said.
Galen said that though vice presidential nominees typically lead the attack on the opposition, he could see the roles reversed if Pence joins the ticket.
"I think he will be able to do what Trump is unable or unwilling to do – try and parse together from Trump's statements something he can articulate as a vision for Trump's leadership," he said.
"No one thinks Mike Pence is going to go give a speech that blows the doors off…. I would venture to say on any given day, Trump will be out attacking Hillary, and Pence will be the one giving the policy speech or holding the town hall meeting."
But Pence's history of taking positions contrary to Trump's could prove troublesome.
In December on Twitter, Pence called Trump's proposed ban on Muslims entering the United States "offensive and unconstitutional."
Pence is also a longtime champion of the free trade agreements that Trump has denounced as harmful to American workers. "Trade means jobs, but trade also means security," Pence tweeted in September 2014.
Democrats, not surprisingly, were harshly critical of Trump's putative selection.
"If Trump picks extreme right-wing Governor Mike Pence as his running mate, he will be doubling down on his divisive and hate-filled approach to politics," the liberal group MoveOn said in a statement.
As governor, Pence focused early in his terms on education and economic issues, winning praise for his communication skills and willingness to work across the partisan aisle.
In 2015, though, he drew nationwide attention and sparked an outcry at home by signing legislation that, critics said, allowed businesses to discriminate against gays and lesbians. After initially standing by the law, Pence signed a hastily passed measure clarifying that such discrimination remained illegal.
He also signed strict antiabortion legislation, which critics seized upon Thursday to press Democrats' political advantage among women.
"Combined with Donald Trump's proposal to criminalize a woman who has an abortion and his threat to appoint Supreme Court justices who will overturn Roe v. Wade, a Trump-Pence ticket could spell out a scary reality for American women and our families," the Pro-Choice America political action committee said in a statement condemning the governor.
Pence has long harbored national ambitions. For a time he considered his own run for president, in both 2012 and 2016.
In May, he gave a muddled endorsement to Trump's rival Cruz just before Indiana's crucial primary, saying he would vote for the Texas senator but heaping praise on Trump and urging Indiana Republicans to make up their own minds. Trump won the contest handily, effectively clinching the GOP nomination.
Pence faces a tight deadline to end his reelection bid. State law bars him from running for both governor and the vice presidency, and Pence has until noon Friday to withdraw his name from the state ballot.
He was facing a competitive rematch against former Indiana House Speaker John Gregg, whom Pence edged out to win the governorship in 2012.
Times staff writers Lisa Mascaro and Seema Mehta contributed to this report.
Twitter: For more political news and analysis follow me @markzbarabak
7:42 p.m.: The story was updated with Trump telling donors he would announce his vice presidential pick over the weekend.
4:31 p.m.: The story was updated with news that Trump had postponed his running mate announcement because of the apparent terrorist attack in France.
3:43 p.m.: The story was updated with new information throughout.