Rep. Zach Wamp’s (R-Tenn.) recently announced 2010 gubernatorial plans touched off an open-seat scramble among Republicans in his Chattanooga-based district, which has been reliably conservative territory.

Wamp’s decision to seek the governorship wasn’t exactly a surprise as the eight-term Congressman had talked openly last year about running in 2010, when Gov. Phil Bredesen (D) will be term-limited out of office. But Wamp’s official entry in the race last week was rather sudden, coming less than 24 hours after popular former Sen. Bill Frist (R) announced he would pass on a run at the governor’s mansion. Frist’s decision to pass also prompted several other Republicans to enter the contest, including Knoxville Mayor Bill Haslam and Shelby County District Attorney Bill Gibbons.

Assuming Wamp doesn’t end his gubernatorial bid before the state filing deadline and decide to return to Congress, Republicans appear to have a slew of possible candidates waiting in the wings in the 3rd district. There is no runoff in Tennessee, and the winner-take-all contests frequently lead to crowded fields, low winning percentages and bloody primaries.

Potential GOP contenders who are starting to garner attention are state GOP Chairwoman Robin Smith, state Sens. Bo Watson and Dewayne Bunch and businessman Wayne Cropp. None have formally announced they are running, but they haven’t exactly removed their name from consideration, either.

“I know there were some dominoes that were set in motion with the announcement” by Frist, Smith said last week. “But that doesn’t mean everyone has to make their declarations known this week.”

Smith acknowledged that supporters are encouraging her to throw her hat into the ring to replace Wamp and that, for now, she’s simply considering the option. She added that she intends to make a final decision by early spring, hopefully by late March.

Bunch has also acknowledged he’s considering a run while Watson and Cropp are playing their cards closer to the vest.

When reached last week, Cropp, a major Wamp campaign contributor over the years, said, “I really do not have any comment on my future plans at this point.”

Meanwhile, a top potential Democratic candidate, Chattanooga Mayor Ron Littlefield, said Monday that despite his name being floated for the race, he will not be seeking Wamp’s seat. He kicked off his mayoral re-election campaign last week.

“Chattanooga is the center of a multi-county, multi-state region and will be experiencing growth at an unprecedented rate in the next few years,” Littlefield said through a spokesman. “I am committed to this community and, while flattered that my name has been tossed around as a replacement for Congressman Wamp, feel that my leadership and experience is most needed here in Chattanooga.”

Littlefield is a former City Council member who won his first term as mayor of the district’s largest city in 2005 after a runoff election. Several Democrats in Washington and Tennessee agreed he would have been one of the party’s best hopes to pick up a district that hasn’t voted for a Democrat in a presidential contest since 1996.

But even with Littlefield out, some Democrats argue that the 3rd district shouldn’t be considered a lock for Republicans.

Randy Button, a former state Democratic Party chairman, said with the right conservative candidate the 3rd district can be competitive. Button, who said he’s not considering a bid in the 3rd, argued that recent presidential election numbers in the district aren’t that much different from those in the nearby 4th district, represented by Rep. Lincoln Davis (D-Tenn.).

Both districts went solidly for Sen. John McCain (R-Ariz.) last fall, and President George W. Bush won the 3rd district with 61 percent of the vote in 2004 while carrying the 4th with 58 percent that same year.

Button said that when he hears talk about Republican invincibility in the 3rd, he’s reminded of similar comments from Tennessee GOPers in the 4th district in 2002.

That year, Republican Van Hilleary was leaving the House after four terms to run for governor. Davis ran as a socially conservative Democrat whose message was that no one on the campaign trail would “outgun me, outpray me or outdaddy me.” In the end, with help from the fiscally conservative Blue Dog Democrats, Davis ended up carrying the district by 6 points.

With the right candidate and the right environment, Button said Democrats could repeat that success again in an open-seat race in the 3rd.