House Republicans appear to be putting immigration reform on hold for two reasons: First, acting now could depress the base’s enthusiasm and imperil the GOP’s chances of taking the Senate; and second, because they think they have the luxury of waiting until 2015 to do reform in time for the 2016 presidential race.

But now those arguments are being strongly disputed by a senior Republican operative with extensive experience in Senate races — Rob Jesmer, who was executive director of the NRSC from 2008-2012. Jesmer argued that if Republicans wait, the politics of immigration will get tangled up in GOP presidential primary politics next year — making reform harder than it is now and increasing the likelihood Republicans will go into another presidential election without having improved relations with Latinos.

“It’s easier to do it now, than to do it later,” Jesmer told me in an interview today. “Presidential politics will consume our party, which will make it more difficult to get it passed. The quicker we start, the quicker we’ll get it behind us. We will severely diminish our chances of winning the presidential election in 2016 if this isn’t solved.”

Jesmer is campaign manger to the pro-reform group Forward US, but his assessment might carry weight with Republicans independently, given his extensive work on Senate races.

Indeed, Jesmer strongly contested the idea that acting on immigration now would harm Republican chances of winning the Senate. And he disputed the widespread claim that it would step on the current advantage Republicans have due to Obamacare.

“I don’t see any data that suggests that this would increase Democratic chances of holding the Senate,” Jesmer said. “The idea that someone who is sitting at home mad at the president about Obamacare is going to wake up in October and say, ‘I’m really mad that Republicans voted to solve the immigration mess, so I’m not going to vote’ — I just find that to be ridiculous.”

“What people are really saying is, ‘Things are going really well now so we can’t do it,'” Jesmer continued. “Are we supposed to wait until things are not going well? It’s never going to be easy to do this, because we have many in our party, and many outside forces, who will oppose this whether we do it tomorrow, next month, next year, or 10 years from now.”

It has been widely accepted on faith that Republicans have no urgency to act on immigration. But little by little, folks are starting to point out that waiting could actually be worse for Republicans. Several GOP consultants made that case in this space the other day, and Chris Cillizza, MSNBC’s First Read crew, and Jonathan Chait have also made good variations of it.

Indeed, the real story here is that for Republicans, the immigration calendar is actually pretty unforgiving. The crux of the issue is this: Either Republicans embrace immigration reform in time for the 2016 presidential race, or they don’t. If they decide not to, that doesn’t ensure a loss, but it’s a pretty big gamble.

However, if they decide they are going to embrace reform, and try to repair the Latino problem in time for 2016, it could actually become harder if they wait — not easier. Indeed, waiting makes it more likely reform could fail after yet another contentious GOP primary debate — saddling Republicans with more negative immigration baggage, heading into another general election.

“The window basically is the next 15 months,” Jesmer says. “And it will be easier to do it this year than next year.”