Former Sen. Chuck Hagel said he voted straight Republican when he cast his first vote, filling out the absentee form on the back of a tank in Vietnam.

The Nebraska Republican crossed party lines yesterday as he endorsed< fellow veteran Joe Sestak in the Pennsylvania Senate race.

Mr. Hagel joined Mr. Sestak at a Mt. Washington press conference, arguing that the Democratic nominee's independence gives him the potential to be part of a new governing coalition of both parties in Washington.

It was the second time in a week that the Democrat had showcased a cross-party endorsement, promoting an image of independence at a time when polling suggests that both major parties are held in low esteem by voters. Mr. Sestak joined New York Mayor Michael Bloomberg, an independent, at a similar event last week in Philadelphia, where he was to return this afternoon for a reprise of the Hagel endorsement.

The appearances came at the end of the week in which several polls showed erosion in Mr. Sestak's competitive position with former Rep. Pat Toomey in the race to succeed Sen. Arlen Specter. After weeks of GOP ads portraying him as a big-spending liberal, Mr. Sestak was intent on shoring up his position with independent voters. The Republican assault on his record continued at the periphery of his morning news conference as a knot of Toomey supporters surveyed the event, holding signs with messages such as, "Joe, I'm in enough debt already,'' and "Hey, Big Spender.''

Mr. Sestak argued that his opponent had supported policies that drove up the nation's debt. He faulted Mr. Toomey for failing to support measures to enforce pay-as-you-go rules in Congress designed to offset new spending with cuts elsewhere in government.

Washington correspondent Daniel Malloy writes the "Pittsburgh On The Potomac" blog exclusively at PG+, a members-only web site of the Pittsburgh Post-Gazette. Our introduction to PG+ gives you all the details.