In the first trip of Obama's second term, the President visited Las Vegas to drum up support for immigration reform, outlining a plan that includes cracking down on employers who hire undocumented workers. NBC's Peter Alexander reports.

Updated 3:34 p.m. ET - President Barack Obama hailed the Senate's bipartisan immigration framework at a major speech on that topic this afternoon in Nevada, but threatened to send his own alternative legislation to Capitol Hill if Congress fails to act.

The president embraced of a statement of principles offered Monday by four Democratic and four Republican senators, which would strengthen border security and employment verification in exchange for a path to citizenship for undocumented immigrants in the United States.

"The good news is that -- for the first time in many years -- Republicans and Democrats seem ready to tackle this problem together," Obama said in his speech in Las Vegas, according to prepared excerpts.

Jason Reed / Reuters President Barack Obama arrives in Las Vegas, Jan. 29. Obama arrived in Nevada to deliver remarks on immigration reform.

"And yesterday, a bipartisan group of senators announced their principles for comprehensive immigration reform, which are very much in line with the principles I've proposed and campaigned on for the last few years," the president also said. "At this moment, it looks like there's a genuine desire to get this done soon. And that's very encouraging."

But in a speech in Nevada -- a Southwestern state that has experienced a boom in its Hispanic population -- the president said he refused to allow comprehensive immigration reform "to get bogged down in an endless debate."

"It's important for us to realize that the foundation for bipartisan action is already in place," he said. If lawmakers fail to advance their own proposal, Obama said he would send legislation to Congress based on his own principles "and insist that they vote on it right away."

He said at the top of his speech: "I'm here because the time has come for common-sense, comprehensive immigration reform."

NBC's Miguel Almaguer spoke with the Barajas family who are among the estimated 11 million undocumented immigrants living in the United States. They are hopeful that President Obama's immigration plan will change their lives.

The president used Tuesday's speech in Nevada to outline many of those principles, which rest on four pillars: strengthening border security, cracking down on employers who hire undocumented workers, streamlining legal immigration and -- most importantly -- offering undocumented workers an earned path to citizenship.

Those pillars mostly resemble the bipartisan Senate framework unveiled on Monday by lawmakers, which has prompted hopes that Congress would finally be able to advance a comprehensive immigration reform law, a priority that eluded Obama during his first term, and President George W. Bush before him.

The primary sticking point in those fights has been the pathway to citizenship, which conservatives deride as "amnesty" for those who have broken the law. Already, some prominent conservatives have expressed their skepticism of the Senate framework for exactly that reason.

"Yes, they broke the rules," Obama said of those undocumented immigrants. "They crossed the border illegally. Maybe they overstayed their visas. But these 11 million men and women are now here."

President Obama lays out his plan for a sweeping immigration reform at a campaign-style event in Las Vegas. Watch his entire speech.

Republicans in particular had been closely watching Obama's actions for cues as to how the administration might handle immigration, and the emerging Senate deal. Republican lawmakers have openly worried that the president might stake out stark positions and oppose some of the enforcement measures included in the Senate framework, namely the trigger that would only allow a pathway to citizenship once the border enforcement mechanisms had been verified.

"There are a lot of ideas about how best to fix our broken immigration system," said Brendan Buck, a spokesman for House Speaker John Boehner, R-Ohio. "Any solution should be a bipartisan one, and we hope the President is careful not to drag the debate to the left and ultimately disrupt the difficult work that is ahead in the House and Senate."

But Florida Sen. Marco Rubio, a rock star to conservatives who's seen as eyeing a run for the GOP presidential nomination in 2016, has taken an active lead in selling this proposal to the right. Rubio has appeared in conservative media to both discourage Obama from opposing enforcement provisions, but also talk up the proposal as the best chance at compromise for Republicans.

"If, in fact, this bill does not have real triggers in there -- in essence, if there's not language in this bill that guarantees that nothing else happens unless these enforcement mechanisms are in place -- then I won't support it," Rubio, a member of the bipartisan gang of eight, told conservative radio host Rush Limbaugh on Tuesday. "But the principles clearly call for that."

But the president generally spoke in broad terms, and did not draw any bright lines as it relates to the Senate proposal.

"I believe we are finally at a moment where comprehensive immigration reform is finally within our grasp," he said.