The White House defended the performance of its top Supreme Court lawyer in arguing for President Barack Obama's health care overhaul, amid criticism from some observers who say he stumbled through a slew of questions from skeptical conservative justices.

Kathryn Ruemmler, who as White House counsel is Obama's top legal adviser, said the administration has every confidence in how Solicitor General Donald Verrilli on Tuesday argued the case that the Affordable Care Act passes constitutional muster.

Answering critics who portrayed Verrilli's performance -- recorded on audiotape by the court and available to the public -- as bumbling, Ruemmler in a statement from the White House called Verrilli an extraordinarily talented advocate who possesses a sharp mind, keen judgment and unquestionable integrity.

The audio of Tuesday's oral arguments reveals that Verrilli coughed frequently, started his sentences over and repeated himself. At one point he paused, said, Excuse me, and took a sip of water before continuing his argument.

Defending the president's landmark legislation in front of the highest court in the land is no easy feat. But some observers expressed shock that a veteran litigator who has argued 17 cases before the Supreme Court struggled to be articulate.

He was passive. He was stumbling. He was nervous, legal analyst Jeffrey Toobin told Politico.

Somewhat embarrassingly, the court's liberal justices appeared to feel it necessary to interject to help Verrilli make his case. Justice Sonia Sotomayor, an Obama nominee to the court, seemed to say she didn't think Verrilli was doing the best job he could when she tried to push him to make other arguments he had made in the past.

I see or have seen three strands of argument in your briefs, and one of them is echoed today, she said.

Justice Ruth Bader Ginsburg also gave Verrilli a nudge when she said, I thought that your main point is that and General Verrilli ... tell me if I'm wrong about this, but I though a major, major point of your argument was that ...

Verrilli appeared to regain composure as he continued his argument, but the damage had been done. Liberal bloggers were particularly harsh on the solicitor general's performance.

Verrilli should be grateful to the Supreme Court for refusing to allow cameras in the courtroom, because his defense of Obamacare on Tuesday may go down as one of the most spectacular flameouts in the history of the court, wrote Adam Serwer of Mother Jones.

MSNBC's Rachel Maddow wrote on her blog that Verrilli was not at the top of his game today, and the word 'choke' is being bandied about quite a bit.

Verrilli's floundering speech worried those who had been confident that Obamacare would be upheld.  However, oral arguments are just small a part of a long, outstretched decision-making progress. 

Oral arguments rarely affect the outcome of the case, and I don't know that today is any exception,  Randy Barnett, an attorney for the National Federation of Independent Business, which is suing to overturn the law, told Politico.