Rivals to the Florida Senator are starting to see him for the threat that he poses in the bitterly contested Republican fight for the presidential nomination.

One-time mentor Jeb Bush is telling voters that Rubio blows off his taxpayer-funded job as a Senator. Chris Christie says Rubio has “never been in a tough race in his life” and would falter against likely Democratic nominee Hillary Clinton. Rand Paul says Rubio is weak on national security and a neo-conservative. And Donald Trump? Well, he’s never met a rival he won’t disparage or mock.

“They attack me more and more,” Rubio said Thursday, shaking his head. All he can do is keep having standing-room-only rallies and intimate meetings in supporters’ living rooms. “Usually it means you’re doing well if someone is trying to pull you down,” he told reporters later.

Taken together, these attacks on Rubio are a reminder what has been true from the start, but easy to forget: Rubio is a talented politician who, if successful, could help a party in dire need of a fresh face. He’s a skilled speaker, a charismatic campaigner and a generation younger than Clinton, Bush and Trump. At the same time, he’s been something of an afterthought in this campaign as loud-mouthed Trump has dominated headlines by insulting women, immigrants, Hispanics and Muslims.

That dynamic, however, seems to be shifting. In New Hampshire, the race has become a contest to be the leading Not-Trump candidate. Rubio’s advisers don’t see him winning over Trump in New Hampshire, but he can certainly have a strong showing—perhaps even besting Bush in a state where his former mentor has gone all-in, or maybe out-pace conservative darling Ted Cruz. “Can he win in New Hampshire? He can win enough and go on,” said Phyllis Woods, a former Republican National Committee member from New Hampshire and a Rubio adviser.

Rubio is having something of a surge, and a strong showing here would nudge more traditional Republicans to start coalescing around one chief alternative to Trump. “The Establishment Republicans are a strong constituency that we cannot ignore,” Woods said. “Anyone saying they want to destroy the Establishment Republicans is going to have a tough time getting enough votes.” And that’s really what Rubio—and his rivals—are counting on. That calculation is why the cluster trailing Trump are turning on each other with barbs in person and on the airwaves.

Rubio is a frequent target, but he’s also punching back against those who want to derail him. He criticizes supporters of Common Core State Standards, education benchmarks states voluntarily adopted and Bush at one time defended. He makes veiled references to Governors who have opted-in with the Democrats’ health care overhaul, chiefly Christie and Ohio’s John Kasich. A pro-Rubio super PAC is spending $1 million ads criticizing Christie’s record in New Jersey.

Rubio blasts rivals who decided to participate in part of the federal law that allows states to expand Medicaid coverage. “It’s structured as a bait and switch,” Rubio says, and voters will be left on the hook for the bill in coming years.

On immigration, he casts himself as the lone candidate who fully understands its challenges, apart from those like Cruz. “I didn’t watch a Frontline series on PBS,” Rubio said. He also swiped at Paul’s proposals that would cut military spending and roll back surveillance. “We’re going to have a real war on terror, not just a rhetorical one,” Rubio said.

But it’s not clear if Rubio’s counterpunches can turn the tables on his rivals, who seem to be working from the same talking points and showing no mercy. A super PAC backing Bush is running ads hitting Rubio’s poor attendance record in the Senate—so many of them that a friendly voter asked Rubio about them Thursday morning at a house party in Bedford, New Hampshire. Bush’s super PAC has spent $23 million on ads in New Hampshire alone, and the spots are clearly breaking through.

“A lot of ads have been playing and they’re saying how you’re not voting. I want to know: What is it that you want to tell us about why it is you’re not voting on those things? Some of them are pretty big issues,” the woman asked Rubio.

Rubio had his answer ready. “When you run for President, there are votes that you’re going to miss,” he said. “When I’m not in Washington, I’m running for President so that we can have a President who is serious about this stuff, not just these show votes.”

He took particular exception to one Bush super PAC ad’s suggestion that Rubio is chasing the White House and shirking his day job in the Senate. “Days after the Paris attacks, Senators came together for a top-secret briefing on the terrorist threat. Marco Rubio was missing, fundraising in California instead,” the narrator in that ad says.

Rubio does his best to shrug it off. “If you take all the other candidates, as Republicans, and put them together no one has had more intelligence briefings over the last five years that I have—if you combine all of the other candidates,” he said.

Still, Rubio’s defensiveness is starting to show. It’s only natural when his rivals are showing no mercy, even tweaking him on his shoe choices. “Boy, are we getting a ton of coverage about a pair of boots,” he said. “This is craziness. Have people lost their minds?”

This article was originally published on Time.com.