Marco Rubio faced attacks from his rival Republican presidential aspirants as they tried to halt the first-term senator's campaign surge by branding him as too inexperienced and unaccomplished to be the next US president.
Young and energetic Rubio, 44, had finished third after Ted Cruz and Donald Trump in the Iowa caucus leaving other top Republican leaders far behind including the New Jersey Governor Chris Christies and the former Florida Governor, Jeb Bush.
Following the crucial Republican debate yesterday - three days ahead of the New Hampshire primary - The Washington Post reported that Marco became the "top target" of others.
Florida Senator Rubio looked "rattled" and faltered as he pushed back with scripted lines about President Barack Obama that Chris Christie mocked mercilessly, the New York Times reported.
"The fact is, Marco, you shouldn't compare yourself to Joe Biden and you shouldn't say that that's what we're doing. Here is exactly what we're doing. You have not be involved in a consequential decision where you had to be held accountable. You just simply haven't," Christie said.
"I like Marco Rubio, and he's a smart person and a good guy, but he simply does not have the experience to be president of the US and make these decisions. We've watched it happen, everybody. For the last seven years, the people of New Hampshire are smart. Do not make the same mistake again," Christie said.
"You know what the shame is Marco? The shame is that you would actually criticise somebody for showing up to work, plowing the streets, getting the trains running back on time when you've never been responsible for that in your entire life," he said.
Meanwhile, Republican front-runner Donald Trump who returned to the debate stage faced a similar assault from a recharged Jeb Bush, the former Florida Governor.
"But what Donald Trump did was use eminent domain to try to take the property of an elderly woman on the strip in Atlantic City. That is not public purpose, that is downright wrong," Bush said.
Trump said that the allegations were incorrect.
"Jeb wants to be a tough guy tonight. I didn't take the property," he said as the two engaged in a war of words on the Key Stone pipeline.
