On the trail

Marco Rubio took full responsibility for his disappointing finish in the New Hampshire primary and apologized for an uneven debate performance that provided fodder to his Republican rivals. "Our disappointment tonight is not on you. It's on me," the Florida senator told the crowd at a downtown Manchester hotel. "I did not do well on Saturday night. That will never happen again." His supporters had been downcast for much of the night, but they cheered loudly for their candidate and chanted his name.

Chris Christie said he's heading home to New Jersey to "take a deep breath" and take stock of his struggling presidential bid. The governor had banked on a strong finish on Tuesday, but he's on track to end up far off the pace despite holding more than 70 town hall events over the past few months.

Donald Trump aired a new television ad that bashes Ted Cruz as "the worst kind of Washington insider, who just can't be trusted" — a play off Cruz's campaign slogan "TrusTed." The two candidates are after the same voters, people who want to shake up the federal government by electing an "outsider" president. The 30-second spot said Cruz "talks from both side of his mouth" on allowing immigrants who are in the country illegally to stay, and took "sweetheart" loans from Wall Street banks when he ran for Senate in 2012. Then the narrator said Cruz's presidential campaign employed "dirty tricks" when it sent word to Iowans on the night of that state's caucuses that Ben Carson might be dropping out.

Ted Cruz said Donald Trump has no choice but to engage in profanity because the billionaire businessman "can't discuss the substance."

John Kasich searched for votes one cup of coffee at a time. The Ohio governor jumped behind the counter at the Red Arrow diner in Manchester, N.H., to pour coffee and even deliver a plate of food. "I don't want to bother you, but I'm going to bother you!" he joked.

Jeb Bush, buoyed by some favorable poll numbers and growing crowds, hammered away at Donald Trump. He said his experience as a two-term Florida governor is a better presidential qualification. Bush said he's determined to knock down Trump because "this guy is not a conservative" and he cannot "win by insulting your way to the presidency."

Associated Press