Florida Sen. Marco Rubio, who saw his poll numbers plummet after signing onto the Gang of Eight's immigration-reform proposal earlier this year, is now openly deriding the idea of comprehensive reform. Talking Points Memo reports:

The most prominent conservative supporter of sweeping immigration reform is calling on Congress to dial back the effort and instead focus on making incremental changes, delivering a significant blow to the prospects of reform.

Sen. Marco Rubio (R-FL) now opposes a bicameral conference committee to reach a final resolution to the Senate-passed bill, his spokesman said, arguing that the support is not there for a comprehensive overhaul and that Congress should act where there is consensus.

"The point is that at this time, the only approach that has a realistic chance of success is to focus on those aspects of reform on which there is consensus through a series of individual bills," Alex Conant, a top spokesman for Rubio, told TPM in an email. "Otherwise, this latest effort to make progress on immigration will meet the same fate as previous efforts: failure."

As I noted in The Skinny last week, the road ahead for comprehensive immigration reform—i.e., any plan that includes a path to citizenship for people now in the country illegally—is rocky. Member of the Arizona business community are flying back to D.C. today as part of a push by the U.S. Chamber of Commerce to get House members on board, but most GOP House members seem more inclined to listen to the Tea Party base than to business types these days.

Dan Nowicki at the Arizona Republic talks to Arizona business leaders who say that President Barack Obama's push for immigration reform may make it harder for House Republicans to go along:

For most of this year, Obama has kept his distance from the legislative action, giving the Senate’s bipartisan “Gang of Eight” of four Democrats and four Republicans the time they needed to craft their bill. The group included Republican Sens. John McCain and Jeff Flake of Arizona.

Because of the delicate political dynamics of the House, Obama’s increasing presence in the immigration debate gives anxiety to some pro-reform business leaders who traditionally have a good rapport with Republicans. The fear is that some GOP partisans who might otherwise support reform could balk if they feel Obama is muscling them.

“It hurts more than it helps,” said Glenn Hamer, president and CEO of the Arizona Chamber of Commerce and Industry, who, with other business leaders, will travel to Washington next week to lobby lawmakers to pass immigration reform. “We understand and we appreciate that this is a big issue for him. It’s a big issue for the country. This would be a good time for the House of Representatives to really pass out its vision for immigration reform.”

In his Thursday statement, Obama acknowledged that his support could provoke new antagonism from his conservative critics, but he emphasized that immigration reform — the top domestic priority of Obama’s second term — has broad-based political appeal and historically has attracted support from Republicans, including former President George W. Bush.

“I know that there are some folks in this town who are primed to think, ‘Well, if Obama is for it, then I’m against it,’ ” Obama said. “But I’d remind everybody that my Republican predecessor was also for it when he proposed reforms like this almost a decade ago, and I joined with 23 Senate Republicans back then to support that reform. I’d remind you that this reform won more than a dozen Republican votes in the Senate in June.”

He added: “I’m not running for office again. I just believe this is the right thing to do.”