Marco Rubio vs Hillary Clinton

Having gone all in, Rubio might get a boost, just as Cruz, the junior senator from Texas, has since he announced his candidacy last month. Right now, though, it’s hard to see how he could challenge the front-runners. Although Rubio was elected to the Senate in 2010 as part of the Tea Party wave, and although he still espouses extreme views on issues like climate change (he’s a skeptic) and same-sex marriage (he opposes it), many people in the conservative movement don’t view him as a true believer. In any case, the right-wing end of the Republican field is very crowded. Rubio’s best hope is probably to position himself as a center-right candidate and hope for a slipup on the part of Jeb Bush, his fellow Floridian.

The 43-year-old freshman senator is the youngest contender in a rapidly-growing race for the presidency, and his speech Monday signaled he’ll aim to turn his youth and relative inexperience into a central calling card of his campaign. That offers him a clear and immediate point of contrast with two of the top contenders in the race, both former Secretary of State Hillary Clinton, who became the first Democratic candidate with her launch on Sunday, and likely GOP contender Jeb Bush.

Rubio wasted no time in taking a swipe at Clinton.

“Just yesterday, a leader from yesterday,” he said, as the crowd erupted in boos, “began a campaign for President by promising to take us back to yesterday. But yesterday is over, and we are never going back.”

Mr. Rubio and most of his Republican rivals will be in New Hampshire this weekend for a state party summit meeting, huddling with groups of elected officials and party activists to make their case. So far, no candidate has risen above the rest.

“My head tells me that Jeb Bush is the only Republican looking presidential at this point, but my heart vacillates a little,” said Barry Wynn, a major Republican donor from South Carolina. “I’ve heard people say, when they listen to Bush in person, he can come across as presidential. But he and the other Republicans need to become sharper, more sure-footed, if one of them is going to beat Hillary and her I’m-like-you message.”