Most Republicans agree that Mike Pence is a solid choice for a presidential running mate.
The Indiana governor is well-respected among conservatives for his measured approach to politics, his stoic demeanor and his positions on issues that matter to the American right. As a former member of Congress who served six terms in the House, Pence already has a rapport with Washington lawmakers who see him as an old-school Republican.
He's also close with House Speaker Rep. Paul Ryan of Wisconsin, making him a natural conduit to smooth over differences between the speaker and Republican nominee Donald Trump.
With the Pence pick, some skeptical Republicans were won over, and others say they see hope for the Trump ticket.
But there are also things Pence cannot do. He won't be able to silence the remaining forces in open revolt inside the Republican party, and he probably won't be able to temper the real estate mogul's "diarrhea of the mouth," as one voter memorably described Trump's habit of saying inflammatory things.
"I hope that Mike Pence can help change Donald Trump's positions, particularly as it relates to his statements about Hispanics," Arizona Sen. Jeff Flake told Politico. "I hope Mike Pence can be a good influence."
Notably, no one has been able to rein Trump in. While it appears the Republican presidential candidate has refined his message in recent weeks and recovered from a disastrous early summer that saw him sink in the polls, Trump usually doesn't go long between saying things that shock people.
Then again, Trump speaks off the cuff. He regularly takes questions from reporters, he phones in to cable news programs, he makes appearances on conservative radio shows, and he's comfortable stopping for impromptu press conferences.
By contrast, the last time Hillary Clinton spoke to reporters was Dec. 4, 2015. It's been 229 days since the Democratic nominee held a press conference or said anything that hasn't been scripted. More than half of 2016 is gone, and a candidate who wants to be president hasn't take a single question from a reporter.
Even if Pence can't smooth Trump's edges, he can serve as an effective attacker, the traditional role of vice presidential candidates. Democratic Sen. Elizabeth Warren, one of the reported forerunners in Clinton's vice presidential search, has been serving as attack dog -- and apparently relishing the role -- for the Clinton camp for the past several months.
Warren didn't waste any time after Trump announced Pence as his running mate, reaching immediately for ad hominems.
Trump and Pence "are a perfect match," Warren tweeted. "Two small, insecure, weak men who use hate & fear to divide our country & our people."
Pence may not be able to temper Trump's words. He certainly won't appeal to Democrats, and he's probably not going to bring in those last few pockets of Republican resistance, the #NeverTrump crowd promising to sit out the election or vote for third-party candidates.
Pence won't convince Trump not to build a border wall. He won't cure the businessman of his habit of praising strongmen like Russia's Vladimir Putin. He can't dampen Trump's nationalism, which is a centerpiece of his campaign.
But if Clinton chooses Warren as her running mate, or another Democrat who equals Warren in willingness to hurl invective, Pence is just the sort of low-key politician who can parry those attacks. The rest is up to Trump.