Florida Senator Marco Rubio endorsed Senate Minority Leader Mitch McConnell over his Kentucky Tea Party primary challenger Sunday morning, signalling a limit to the intraparty resentments following Republicans' failed effort to defund Obamacare throughout the government shutdown.

Appearing on Fox News Sunday, Rubio was asked by host Chris Wallace if he supported the Kentucy senator against Matt Bevin, a Tea Party challenger, following McConnell's decision to end the quest to defund Obamacare by striking a deal with Democrats to raise the debt ceiling and reopen the government.

"I do," said Rubio, noting that McConnell faced a difficult task in keeping Republicans united on tactics. "It’s not an easy job to do," Rubio said of leading the GOP caucus and representing his home state.

Rubio joins fellow Tea Party senator Rand Paul in getting behind McConnell's run. The Senate Conservatives Fund, a political action committee founded by former South Carolina senator and current Heritage Foundation president Jim DeMint, has endorsed Bevin.

His endorsement of McConnell, however, doesn't mean that Rubio necessarily thinks that the effort to defund the health care law through the government funding process was a mistake.

“I think, in hindsight, in any endeavor one gets in there are lessons to be learned," Rubio said of the push to obtain changes to Obamacare throughout the two-and-a-half week shutdown. "Are there any lessons we’ve learned in the last three weeks that would help us get results? I think we’ll have that conversation."

And Rubio refused to directly promise not to risk another government shutdown again, blaming the past few week's breakdown on President Obama and Senate Majority Leader Harry Reid, rather than Republicans seeking major changes to Obamacare.

"The American Dream is under assault," Rubio said of the health care law and Obama's broader agenda. He also bashed the troubled ongoing rollout of the health care law's online health insurance exchanges, saying that "in the 21st century, setting up a website where people can buy something, is not that complicated. People do it every day.”

Rubio stopped short, however, of calling for Health and Human Services Secretary Kathleen Sebelius' resignation, saying that he's "not one" for immediate calls for officials to step down. Responding to Wallace's question about Sebelius refusing to appear before a House commitee to answer questions about the law's implementation, Rubio did say that her "refusal to testify and be transparent is undermining her credibility" and could ultimately result in her having to step down.

The administration is also to blame for the failure of Congress to progress on comprehensive immigration reform this year, Rubio claimed, because conservatives are afraid that Obama officials would not enforce the border security provisions of a deal on immigration.

"You have a government and a White House that has consistently decided to ignore the law or how to apply it -- look at the health care law; the laws on the books; they decide what parts of it to apply and which parts not to apply," said Rubio. "What's not to say that this White House won't come back and cancel the enforcement aspects of it?" he asked.

Obama needs to be "realistic" about the fact that his administration's selective enforcement of other laws on the books has "undermined" some Republicans' willingness to strike a deal on immigration, Rubio said. "And quite frankly, it's difficult to find a good answer to that. I think they make a very legitimate point," said Rubio.