It's officially an election year, and we all know what that means: Claws are out among the candidates vying for the presidential nomination.

Nowhere was that more evident than at Thursday's Republican debate, at which the top candidates expanded their ire from President Obama towards each other. The air was particularly hostile between Ted Cruz and Donald Trump, who have been engaged in a war of words over Trump questioning the Canadian-born Cruz's nationality. "If you become the nominee, who the hell knows if you can even serve in office?" Trump asked Cruz at one point.

"I'll tell you what. If this all works out I'm happy to consider naming you as VP and so if you happen to be right, you could get the top job at end of the day," Cruz retorted.

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Coming 48 hours after President Obama called for "respectful debates" in his State of the Union address and noted that politics should bring out the best, not the worst, in our country's leaders, it seems his words may have fallen on deaf ears.

Here are the most pointed zingers from the debate:

Trump, on why he's raising questions about rival Cruz's nationality: "He's doing a little bit better [in the polls]. I didn't care before."

Cruz, criticizing Trump's "New York values": "Everyone understands that the values in New York City are socially liberal, are pro-abortion, are pro-gay marriage, focused around money and the media."

Chris Christie, cutting off Marco Rubio during a discussion of tax policy: "You already had your chance, Marco. You blew it."

Rick Santorum, when his closing statement ran long: "I know I'm out of time, but I'm going to take some of Rand Paul's time." (Paul skipped the debate.)

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Of course, not all the one-liners were directed at each other. Carly Fiorina got in a dig at Democratic candidate Hillary Clinton when she noted, "Unlike another woman in this race, I actually like spending time with my husband," and Jeb Bush also piled on, bringing up Clinton's email scandal. "If she gets elected, her first 100 days, instead of setting the agenda, she might be going back and forth between the White House and the courthouse," he cautioned. Fellow Democrat Bernie Sanders was also a target, with John Kasich predicting: "We're going to win every state if Bernie Sanders is the nominee. That's not even an issue."

Ben Carson, upon getting asked his first question, also quipped: "I'm very happy to get a question this early on. I was going to ask you to wake me up when the time came."

Did you watch Thursday's Republican debate? Who do you think won?