UPDATE: WASHINGTON (AP) -- Republican Sen. Ted Cruz has ended a marathon Senate speech opposing President Barack Obama's health care law after talking for 21 hours, 19 minutes.
The tea party conservative stopped speaking at 12 noon EDT Wednesday, sitting down to yield the floor. The Texas freshman began talking Tuesday afternoon, seeking the urge defunding of the 3-year-old health system overhaul. Fellow conservatives helped by making occasional remarks.
Cruz had virtually no chance of prevailing.
The Senate debated the House bill defunding the health care law while preventing a government shutdown on Tuesday. Cruz wanted to derail it because Senate Democrats have the votes to remove the health care provision before sending the bill back to the House.
Many Republicans opposed Cruz's effort, fearing their party might be blamed if the government closes.
WASHINGTON (CNN) -- Ted Cruz says he wasn't elected to the Senate to stay quiet. And his refusal upon entering Congress to observe its protocol to sit back and learn like a freshman, as expected, rubbed some of his more senior colleagues the wrong way.
And while he has angered much of his party over his crusade against President Barack Obama's health care law and the potential government shutdown it could cause, Cruz says he's standing for the same principles that got him elected.
On Tuesday, he took that edict to the Senate floor in support of his plan to defund Obamacare, saying he would speak "until I am no longer able to stand." And Wednesday morning he was still talking.
But his marathon appearance will not do anything to block Obamacare funding with a key procedural vote on the issue still scheduled for Wednesday. Instead, Cruz said his speech was to simply "make D.C. listen."
Critics question his motives, though --- is this about his principles or about presidential aspirations?
Mobile users watch video here: http://nbcnews.to/16qekIE
CNN political analyst Gloria Borger said his Republican detractors think Cruz is putting his political career above all else.
"While many others have, no doubt, come to the Senate in the past as a springboard to the presidency, it's hard to recall someone who has created as much controversy within his own party," Borger said.
Cruz has been in Washington for less than a year, but his short stint has been an effective lesson in partisan politics. Only history will tell, however, if his tactics will be worth repeating.
The Texas Republican's counterparts in the House of Representatives have tried 42 times to roll back Obamacare, but their efforts have gone nowhere in the Democratic-controlled Senate.
Cruz has upped the ante. His latest battle to disrupt Obamacare is tied to funding the government in the new fiscal year that starts on October 1. The House passed the measure last week. But Senate Democrats are not about to allow the health care bill to be unraveled, therefore putting at risk a government shutdown.
Cruz's refusal to give up the fight has rankled many of his fellow Republicans, widening divisions in a splintered party. Democrats, meanwhile, are sitting back and watching the intraparty fight.
Who is this guy?
His effectiveness at political debate has landed Cruz in many successful places. He was elected to the Senate in 2012, after rebuking the Republican establishment and winning the Republican primary, paving the way to a general election victory.
Previously, he was the youngest solicitor general of Texas and has argued multiple cases before the Supreme Court. He got his start at Princeton as head of the debate team and then honed his skill at Harvard Law School.
What's his fight?
Cruz did not take his Senate responsibilities lightly. As a freshman, he refused to stand on the sidelines until he's gained a measure of seniority, a common tradition in Washington. Instead, he was loud and opinionated.
"I find it amusing that those in Washington are puzzled when someone actually does what they said they would do," Cruz told CNN in February. "At the end of the day, I was elected to represent 26 million Texans and to speak the truth. You know, I think a lot of Americans are tired of politicians in Washington in both parties who play games.
Cruz was elected, promising to shrink government, especially the new health care law. That battle has been embraced by most Republicans in Congress, but his latest tactic has frustrated many.
New York Rep. Peter King has been an outspoken critic of Cruz' latest crusade --- at one point calling him a "fraud."
"Whether it's Custer, whether it's kamikaze, or whether it's Gallipoli or whatever, we are going to lose this," the New York Republican said on CNN's "The Situation Room" last week.
And Republican Sen. Bob Corker of Tennessee tweeted that he "didn't go to Harvard or Princeton" but that he "can count" that Democrats outnumber Republicans in the Senate.
But Cruz said to let his critics talk.
"If you get outside of Washington, D.C.,