Joe Kennedy, whose family name is synonymous with American politics, announced Friday that he will not seek re-election to Congress this November.

"This last year has brought me a new recognition of our own vulnerabilities and the vagaries of life," Kennedy told reporters. The curly-haired Democrat referred to the Dec. 31, 1997, death of his brother Michael and said, "I want to focus . . . on my responsibilities to my own family, both my immediate family and my larger one."Michael Kennedy died in a skiing accident in Colorado.

Asked if by his remarks Kennedy, the eldest son of the late Sen. Robert Kennedy, was saying he would not seek elective office again, the congressman smiled and replied, "No, I'm certainly not."

When this term ends in December, Kennedy said he will direct his attention to Citizens Energy, the Boston-based not-for-profit energy company he founded before running for Congress.

"Listen, I think that there are times when you have to get your priorities right," Kennedy said.

"I mean the fact is, as all of you are well aware, my brother was killed just a couple of months ago, and that requires me to take up my responsibilities here (at Citizens Energy Corp.) and my responsibilities to my family. . . . But I don't rule out the possibility of running for public office, but I think there are many ways to serve the public good.

"I believe that public service is not limited to public office. I won't be campaigning for Congress, but I will continue to be involved in the campaign to end child hunger here in Massachusetts," Kennedy said with his wife, Beth, at his side.

Sen. Edward Kennedy, the congressman's uncle and Massachusetts' senior U.S. senator, told reporters, "I respect his decision and his strong dedication to Citizens Energy, but I'll miss him very much in the House.

"Joe has Bobby's deep sense of commitment to helping others. He's been one of Congress' most powerful voices for helping those in need, and he's made an extraordinary difference for large numbers in this country and around the world."

Rep. Patrick Kennedy from Rhode Island, Edward Kennedy's son, issued a statement saying, "My cousin's voice will be tremendously missed in Congress . . . Joe has been a great help to me during the four years that we have been colleagues in Congress, and I will miss him."

The past 12 months have seen the political hopes of the Democrat from Boston crushed by one Kennedy family tragedy after another.