CASTINE – Before U.S. Sen. John McCain took to the dais Saturday to deliver the commencement address at the Maine Maritime Academy, he spoke briefly with a group of reporters and college administrators about revamping Social Security, protecting the nation’s borders and running for president.

The Republican senator from Arizona said he is hopeful that Democrats and Republicans can reach agreement on bolstering the Social Security system.

“For the American people, it is not a question of whether, it’s a question of when the system is going to go bankrupt,” said McCain, who sat with fellow Republican Sen. Susan Collins of Maine while answering questions from the media inside a campus lecture hall. Collins later would introduce McCain to the crowd during commencement exercises.

“There’s no easy answer to [Social Security],” he told reporters and MMA administrators, “but the problem is a symptom of the bitter partisanship that exists in Washington today, which does not work to the benefit of the American people.”

McCain also said he is troubled by the billions of dollars the country is spending to build military ships and planes.

“We have to do something about the escalating cost of ships,” he said. “We are going to have to make some tough decisions, because right now I don’t see us on the path to providing enough ships to carry out the responsibilities that we have around the world.”

When asked about immigration, McCain criticized the federal government, saying it hasn’t done enough to protect the nation’s borders. Frustrated citizens are taking things into their own hands, he said, noting the Minuteman Project, a group of civilians voluntarily patrolling the border between Arizona and Mexico to search for people crossing illegally. The group recently announced plans to expand its operations to the Canadian border.

On Saturday, McCain called immigration “the most serious issue we face.” He has been working with Sen. Edward Kennedy of Massachusetts on an immigration reform initiative.

“If you walked on the streets in Phoenix today and asked what is the number one issue, they wouldn’t say Social Security,” he said. “They’d say immigration.”

When asked whether he would run for president in 2008, McCain said he has yet to make a decision.

“Senator Collins calls me every morning and every evening and urges me to do so,” he said. “But I’m going to wait a couple of years and then make a decision.”

McCain’s trip to Maine was a quick one; he arrived Friday and left Saturday. He said he heard about Castine from his administrative assistant, Mark Salter, who vacations in the area every August with his wife and children.

While in town, the senator took a 2 1/2-hour walking tour of the campus, went on a morning tugboat ride and ate a lobster roll and ice cream at Castine Variety on Main Street.