WASHINGTON, March 21 (Reuters) - U.S. Supreme Court justices on Wednesday appeared sympathetic to the argument that Secret Service agents have immunity from a lawsuit by a Colorado man arrested after he confronted then-Vice President Dick Cheney and criticized his Iraq war policies.

In hearing arguments, the justices seemed likely to rule for the Obama administration and for the agents, whose lawyer argued they cannot be held personally liable for damages because the arrest had been supported by sufficient cause.

Deputy Solicitor General Sri Srinivasan, arguing for the administration, and Sean Gallagher, representing the two agents, said allowing such lawsuits would make the agents hesitant while protecting the president or the vice president.

"We believe that it is important for Secret Service agents acting in this protective capacity to have the requisite breathing room in order to make decisions in life-or-death or imminent-threat situations," Gallagher said.

Srinivasan also argued for immunity for the agents that would protect them from such lawsuits.

Justice Stephen Breyer seemed sympathetic to the argument made by the government and by the lawyer for the two agents.

"I see the problem of protecting people in public life; I see the problem in protecting the president," he said. "The president's ... life is at stake."

Justice Antonin Scalia agreed and said there had been probable cause for the arrest. "So long as they have good reason for an arrest, it doesn't matter," he said.

The Colorado man, Steven Howards, claimed in his lawsuit that the agents retaliated against him for exercising his constitutionally protected free-speech rights.

Howards was arrested after he approached Cheney during a June 16, 2006 visit to a mall in Beaver Creek, Colorado. When Howards learned Cheney was at the mall, a Secret Service agent said he overheard Howards say into his cell phone, "I'm going to ask him (Cheney) how many kids he's killed today."

Howards waited to meet with Cheney, who was greeting people, shaking hands and posing for photographs. He then confronted Cheney and told him his "policies in Iraq are disgusting."

As Howards departed, he touched Cheney's right shoulder with his open hand.

Howards denied assaulting Cheney when questioned by one of the agents. The other agent confirmed he had witnessed the incident and demonstrated how Howards had contact with Cheney.

The two agents decided to arrest Howards, who was turned over to local law enforcement authorities and charged with harassment under state law. The charges were later dismissed.

Howards then sued, claiming he had been arrested unlawfully and seeking financial damages from the two agents.

David Lane, an attorney for Howards, argued the lawsuit should be allowed to proceed. But Chief Justice John Roberts asked Lane whether it had been reasonable for the agents to arrest Howards.

"You see somebody who said (Cheney's) policies are disgusting, that person touches the vice president, he ... lies to you. He comes back, he's carrying a bag and he's wandering around," Roberts said, adding that he was trying to summarize what might have been going through the agent's mind at the time.

Justice Samuel Alito asked Lane whether there was a record of retaliatory arrests by Secret Service agents against people who make critical comments of the president and vice president.

A ruling in the case is expected by the end of June.

The Supreme Court case is Reichle v. Howards, No. 11-262.

For Reichle: Sean Gallagher of Polsinelli Shughart.

For Howards: David Lane of Killmer, Lane & Newman.

(Reporting by James Vicini)

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