Rubio is one of eight senators who, on Monday, unveiled a bipartisan framework for passing immigration reform. The framework includes creating a pathway to citizenship, increasing the number of visas for high-skilled immigrants, implementing an employer verification system and setting up a new guest-worker program.

"Well look, I love and respect Marco. I think he's just amazingly naive on this issue. This is the same old formula that was dealt with before, including when it passed in 1986, and that is promises of enforcement and immediate amnesty," Vitter said in an interview on the Laura Ingraham radio show released Wednesday. 

"And of course the promises of enforcement never materialize, the amnesty happens immediately — the millisecond the bill is signed into the law. The same is true here. No, they won't be citizens immediately. They will be legal, they will have a full right to stay in this country forever legally. And then the only question is how long does that take? It's gonna happen. I don't know if it's a year, five years longer but citizenship is guaranteed at that point as a practical matter."

The framework also requires strengthening border enforcement before the new pathway to citizenship is offered. Vitter expressed skepticism about that provision.

"Look, as soon as you give these people a legal status, to say that you're gonna reverse that is ridiculous," Vitter said. "It'll never happen. As soon as you give them a legal status, they are here forever, and probably they're citizens soon thereafter."

Instead of the senators' immigration framework, Vitter wants to see a "piecemeal" approach, he said.

"First of all, I think we need to focus on that this is comprehensive reform. To me that is a really negative buzzword," Vitter said. "As a conservative I'm usually against anything 'comprehensive' because that's big government with all sorts of unintended consequences. 

"Obamacare was comprehensive health reform — same thing. Instead, I favor a step-by-step approach so that we can focus on enforcement and build public confidence on that. Prove that case first and it's a pretty reasonable demand from the public that we prove ourselves on that because we've failed miserably every time that's been promised."

While both Democrats and Republicans have expressed interest in passing immigration reform in 2013, a few senators said they are opposed to aspects of the new framework. Besides Vitter, Sens. Jeff SessionsJefferson (Jeff) Beauregard SessionsTrump administration creating family reunification task force: report Mexican airline pledges to reunite immigrant families separated by Trump policy for free Jennifer Lopez sounds off on Trump immigration policy MORE (R-Ala.) and Ted CruzRafael (Ted) Edward CruzThe Hill's Morning Report — Sponsored by PhRMA — Immigration drama grips Washington Senate Gang of Four to meet next week on immigration Live coverage: High drama as hardline immigration bill fails, compromise vote delayed MORE (R-Texas) have suggested they oppose parts of the framework. Sen. Mike LeeMichael (Mike) Shumway LeeOvernight Energy: EPA declines to write new rule for toxic spills | Senate blocks move to stop Obama water rule | EPA bought 'tactical' pants and polos Senate blocks bid to stop Obama water rule GOP senators introduce bill to prevent family separations at border MORE (R-Utah.), who was involved in crafting the framework, walked away from the discussions because he disagreed with creating the pathway to citizenship.