WASHINGTON — Ted Kaufman, a Delaware Democrat who for decades has been a political adviser to Sen. Joe Biden, D-Del., was sworn in today to fill the Senate seat Biden relinquished to become vice president.

Kaufman, 69, has made clear that his emergence into the public spotlight will be brief: he has said he does not intend to stay in the Senate beyond 2010.

Delaware Gov. Ruth Ann Minner, who appointed Kaufman to fill Biden's vacated Senate seat, joined Biden in watching the swearing-in from the visitors' gallery. Biden, who will become Vice President Tuesday, resigned Thursday after 36 years in the Senate.

Kaufman served on Biden's Senate staff from 1973 to 1994, including 19 years as chief of staff, and has held senior positions in all of Biden's national campaigns.