Despite the early snow, the campaign for president is getting pretty heated up in Iowa and the first-in-the-nation primary state of New Hampshire.

A Super PAC supporting former Florida Governor Jeb Bush’s campaign for president, Right to Rise USA, launched its first negative television ad, calling out Florida Senator Marco Rubio for missing national-security Senate hearings to campaign for president.

“Over the last three years, Rubio has missed important national-security hearings and missed more total votes than any other senator,” the ad narrator says, according to The Des Moines Register.

“Politics first: That’s the Rubio way,” the ad concludes.

Rubio’s campaign spokesman Alex Conant called the ad sad and dishonest. “Bush’s team dishonestly omits that Marco is on the Senate’s Intelligence Committee, where he attended the highest-level briefings on the Paris attacks,” Conant said in a statement. “No other candidate for president has received more classified Intelligence briefings or better understands the threats facing our nation today than Marco. It’s sad to see Jeb’s ‘joyful’ campaign reduced to such intellectual dishonesty.”

New Jersey Governor Chris Christie also slammed Rubio for skipping the Senate vote on the recent omnibus spending bill while expressing his opposition to it. “Dude, show up to work. Show up to work and vote no. And if you don’t like it, quit,” Christie said during a town hall meeting in Iowa on Tuesday.

“He gives a good speech, Marco, and I want to hear his stirring speech that’s going to try to persuade people on the floor of the Senate not to vote for this awful spending bill, except he never showed up,” Christie said according to TIME. “He was totally opposed to it and didn’t go there to vote no. Then what’s it matter that you’re opposed to it? He matters as much as I do. I don’t have a vote in the Senate. He has one just didn’t go. Only in Washington could you have the guts to stand up and say I’m against something that you have a vote to vote no on and then just not go and then put out a press release after it gets passed and say this is why I was opposed to it.”

The spending bill appropriated $3.1 billion in security assistance to Israel for Fiscal Year 2016. It also included $487 million for US-Israel missile defense programs and $40 million for a new US-Israel tunnel detection program. This may explain why Rubio decided to skip the vote rather than oppose the bill and be on record voting against funding for Israel’s military assistance. During the last GOP TV debate, Rubio hit Texas Senator Ted Cruz over his vote against the Defense Authorization Act, which “by the way, funds the Iron Dome and other important programs.”

Rubio is tied with Christie for 2nd or 3rd place and slightly ahead of Jeb in recent polls of New Hampshire primary voters.