Rep. Bart Gordon’s (D) surprise retirement announcement Monday set off a scramble as potential successors on both sides of the aisle in middle Tennessee’s 6th district began jockeying for position in the newest open-seat contest of the 2010 cycle.

The conservative seat, which Sen. John McCain (R-Ariz.) won by 25 points in the 2008 presidential race, is certainly a golden opportunity for Republicans. It includes several suburban Nashville counties that have become one of the fastest-growing Republican areas in the state in recent years.

But Democrats insist that even without Gordon, they can be competitive in a district that Democratic Gov. Phil Bredesen won with 52 percent in 2002 and 67 percent in 2006.

“That seat has sort of trended Republicans for years,— Tennessee Democratic Party spokesman Keith Talley said. But “those people over there are middle of the road folks, and that’s why they kept sending Congressman Gordon to Congress— for 13 terms.

On the Republican side, two candidates who had been quietly building their 2010 campaigns moved up their announcement schedules and formally entered the race Monday.

One of those candidates, state Sen. Jim Tracy, was on Capitol Hill earlier this month meeting with the National Republican Congressional Committee about getting into the contest.

Tracy had already hired Nashville-area political strategist Mike McCrady, who has worked on Tennessee state legislative races and in the 2008 cycle worked for Florida 22nd district GOP nominee Allen West. McCrady said Monday that internal polling had shown Tracy ahead of Gordon but within the margin of error in a hypothetical matchup.

Tracy, a former teacher who also owns an insurance business, represents a little more than a third of the district’s population.

Nashville-based conservative talk radio show host Steve Gill, who ran against Gordon twice in the 1990s and came within about 2,000 votes of winning the seat in 1994, said Tracy brings a proven electoral ability to the contest but “he faces a bit of a challenge in that I don’t think this is a strong incumbent year.—

“As a state Senator, he kind of has that ‘I’m in the government and I’m here to help you’ taint,— Gill said.

Gill, who lives outside the 6th district and said he has no intention of running again, said the local anti-incumbent mood may benefit former Rutherford County GOP Chairwoman Lou Ann Zelenik, who has sought to embrace the “tea party— movement since joining the race in October.

Zelenik, who has deep pockets and a compelling personal story as a successful construction business owner, has made a point of attacking career politicians. Before Monday she was already on the air with radio ads that introduced her to voters and bashed Gordon for his record during his quarter-century in Congress.

“Part of the groundswell we have seen this year was to take power from the hands of professional politicians and give voice to the men and women who work hard, create the jobs and pay the bills,— Zelenik said in a statement Monday in the wake of Gordon’s announcement.

Another GOP candidate who is running on the anti-politician platform is Kerry Roberts, a Nashville businessman who owns one of the largest bicycle chains in Tennessee.

“We have an opportunity to move away from politics as usual and toward fresh ideas and new leadership,— Roberts said in his official announcement Monday.

Zelenik and Roberts may have to fight off more than one member of the Tennessee state Senate in the GOP primary.

State Sen. Diane Black (R) told state newspapers Monday that she’s also considering the contest.

Other Republicans already in the race include retired Army Reserve Maj. Gen. Dave Evans and Realtor Gary Mann.

While national Republicans had expressed an early interest in Zelenik, insiders said Monday that Gordon’s exit from the race makes Washington involvement in a primary less likely.

That may be a sign of just how confident the party is about the 6th district since the National Republican Congressional Committee has given every indication it intends to stay involved in the 8th district GOP primary as it looks to target the seat of Rep. John Tanner (D-Tenn.), who announced two weeks ago that he would retire in 2010.

Talley, the Tennessee Democratic Party spokesman, expressed his hope that Republicans will get caught up in a nasty primary and said the state party will work to keep any Democratic primary from becoming a bruising affair.

Democratic Congressional Campaign Committee Chairman Chris Van Hollen (Md.) said the party can retain the seat with “a Democrat who shares Chairman Gordon’s commitment to putting progress before partisanship on behalf of Middle Tennessee.—

Among the early names being floated by Democratic insiders as possible replacements for Gordon in the 6th district are state Rep. Mike McDonald, Wilson County Sheriff Terry Ashe, state Rep. Hank Fincher, Murfreesboro Mayor Tommy Bragg and former state Sens. Andy Womack and Jo Ann Graves.

McDonald acknowledged Monday afternoon that he was mulling jumping into the race.

“I have had a number of phone calls from Democrats here in the state asking me if I’d be interested in running and some cases encouraging me to run,— he said.

Fincher said he was “definitely considering— the race and added that just because the district is conservative doesn’t mean that Republicans will have an advantage in the open-seat contest.

“Republicans don’t have the exclusive claim to conservative values in Tennessee,— Fincher said. “I think a Democrat who has the independent, conservative values of this district will go toe-to-toe with anyone the GOP puts up.—