Sen. Rubio’s point of no return

Legislating in the Senate usually goes like this: A senator introduces a bill, touts it and puts pressure on the House to take it up.

But Sen. Marco RubioMarco Antonio RubioOvernight Defense: Senate passes 0B defense bill | 3,000 US troops heading to Afghanistan | Two more Navy officials fired over ship collisions Senate passes 0B defense bill Trump bets base will stick with him on immigration MORE has taken a very different approach. The Florida Republican, who helped craft the Gang of Eight immigration reform bill, has recently said the legislation should be altered and can’t pass the GOP-led House unless it is.

Those comments sparked speculation that Rubio was getting cold feet. After all, the reform bill has been taking hits from both the left and the right.

But the senator on Tuesday dismissed any notion that he is distancing himself from the bipartisan plan. The possible 2016 White House candidate believes the immigration bill should be improved through amendments. As far as his comment about the House is concerned, Rubio says he was just making a realistic observation.

Sen. John McCainJohn Sidney McCainSenate's defense authorization would set cyber doctrine Senate Dems hold floor talk-a-thon against latest ObamaCare repeal bill Overnight Defense: Senate passes 0B defense bill | 3,000 US troops heading to Afghanistan | Two more Navy officials fired over ship collisions MORE (R-Ariz.), also a member of the gang, maintains that there is backing from right-leaning House members, including Budget Committee Chairman Paul RyanPaul RyanRyan: Graham-Cassidy 'best, last chance' to repeal ObamaCare Ryan: Americans want to see Trump talking with Dem leaders Overnight Finance: CBO to release limited analysis of ObamaCare repeal bill | DOJ investigates Equifax stock sales | House weighs tougher rules for banks dealing with North Korea MORE (R-Wis.).

Over the last several weeks, The Hill has talked to some House conservatives about the proposal. It is true that they are not fond of the Gang of Eight’s bill, most notably its provision of a path to citizenship.

But the gang is a tight group, and all its members are in a boat together. Rubio is tasked with steering that boat through rough waters on the right.

On Monday, Heritage Foundation President Jim DeMint went on the attack, releasing an analysis that says the bill’s price tag would be $6.3 trillion.

Rubio has been respectful of DeMint, but on Tuesday he called Heritage’s findings “flawed.”

He faulted the “single premise” that “these people are disproportionately poor because they have no education, and they will be poor for the rest of their lives in the U.S. Quite frankly that’s not the immigration experience in the U.S.”

In many ways, Rubio has little choice but to stick with the legislation. In 2012, he said he was going to unveil the GOP version of the Development, Relief and Education for Alien Minors (DREAM) Act, but he backed away from that plan after accusing President Obama of playing election-year politics.

There is no doubt that he must stay with the Gang of Eight if the bill, or some version of it, is going to become law. Without his imprimatur, conservative members will vote “no” and the legislation will die.

If that happens, Obama would suffer a stinging setback. But so would Rubio.

The freshman senator is working on a range of issues in this Congress, including a bipartisan education bill with Sen. Chris CoonsChristopher (Chris) Andrew CoonsRaising awareness about maternal health worldwide on National Bump Day Senate plans hearing for bills to protect Mueller Entering a new era of African investment MORE (D-Del.). Last year, he delivered speeches on foreign policy and visited the military prison at Guantánamo Bay.

Still, Rubio’s 2016 presidential run — if he launches a bid — will be shaped around the success or failure of immigration reform.