(AP) — Republican U.S. Sen. David Vitter and his Democratic challenger, Charlie Melancon, painted each other as partisan political puppets as they signed up for the Senate race Wednesday on the first day of qualifying for fall elections.Melancon predicted a “dirty” race as Vitter seeks re-election to a second, six-year term in his first time facing voters after a 2007 prostitution scandal.Qualifying is the official opening of Louisiana’s campaign season, when candidates file the paperwork and pay the fees required to run for office. The sign-up period runs until Friday at 5 p.m., but most of the announced candidates for the top races registered Wednesday.Six of Louisiana’s seven congressmen signed up for re-election bids: Republican U.S. Reps. Steve Scalise of Jefferson, Joseph Cao of New Orleans, John Fleming of Minden, Rodney Alexander of Quitman, Bill Cassidy of Baton Rouge and Charles Boustany of Lafayette. Fleming and Cassidy sent employees to register for them.The state’s sole Democratic congressman, Melancon is leaving his U.S. House seat representing southeast Louisiana to run against Vitter.The incumbent senator and his chief opponent arrived within the same hour at the Secretary of State’s Office to register for the Senate race, and each was met by a small pack of sign-waving protesters.Vitter talked of Melancon’s support of President Barack Obama and Melancon’s vote for the federal stimulus package. Melancon portrayed himself as a centrist and Vitter as a GOP obstructionist who works for his party, rather than the state.”It has been hard-core, right-wing partisan politics, period,” Melancon said of Vitter’s first term in the Senate. He described Vitter as “an uptown New Orleans boy who went to private school and went to Harvard. He’s never hunted or fished.”Vitter called himself a leader on conservative issues and said, “We need to have the proper checks and balances against what is in many ways a radical Obama agenda, and on that point there are stark differences and there will be a clear choice between me and my opponent.”It was Vitter’s first time talking to a bank of reporters since an ABC News report two weeks ago disclosed one of his aides had repeatedly run into trouble with the law, and pleaded guilty two years ago to a knife-wielding altercation with an ex-girlfriend. The aide, Brent Furer, resigned June 23, after the story broke, and women’s groups have blasted Vitter for allowing Furer to remain on staff after the guilty plea.Vitter sidestepped nearly all questions about the resignation, refusing to explain why he kept Furer on staff. He said Furer was disciplined in 2008, but he wouldn’t say how.Four other, lesser-known candidates also signed up for the Senate race, including a Libertarian, two independents and a Democrat who will force Melancon to run in the Aug. 28 party primary before advancing to the Nov. 2 general election.Melancon’s exit from the U.S. House leaves a rare, vacant congressional seat. Three candidates have signed up so far in the 3rd District race representing much of coastal, south Louisiana: Hunt Downer, a Republican former state House speaker and retired major general in the Louisiana National Guard from Houma; Jeff Landry, a Republican lawyer from New Iberia; and Ravi Sangisetty, a Democratic lawyer from Houma.Despite a national wave of discontent with incumbents, three congressmen — Scalise, Cassidy and Boustany — didn’t pick up opponents Wednesday.–Contact The Daily Reveille’s news staff at [email protected]