Florida Republican Rep. Adam H. Putnam ’s decision to run for state agriculture commissioner in 2010 was unexpected, and it set up a possible free-for-all race for the 12th District seat he is leaving after five terms. So two serious candidates, one in each major party, have tried to get a jump on their potential competitors by launching their House campaigns early.

Nonetheless, the quick starts for Republican Dennis A. Ross, a former state representative, and Democrat Lori Edwards, the supervisor of elections in central Florida’s Polk County, do not necessarily preclude crowded primaries on both sides.

Ross has put on an impressive show of securing key support with 18 months to go until the August 2010 primary. He has endorsements from Jeb Bush, the state’s governor from 1999 to 2007 and brother of former President George W. Bush ; current Florida GOP Reps. Connie Mack , Ginny Brown-Waite , Jeff Miller and Gus Bilirakis ; and additional former and current Republican officeholders.

“I’ve got to show that I’m the odds-on favorite,” Ross told CQ Politics when asked if he was attempting to clear the primary field of serious competition. He added, “When Congressman Putnam made his announcement, it was important for me to do the same thing, because this is a 20-month marathon.”

Putnam announced in February that he will vie for the state agriculture post. He was just 33 years old in 2007 when he became chairman of the House Republican Conference, the party’s third-ranking leadership post. But his rise in the House was derailed by a leadership shake-up that followed major Republican losses in the 2006 and 2008 campaigns.

Putnam ran strongly at home — taking more than 57 percent even in the tough 2008 election year — while touting a consistently conservative House voting record. And Ross believes that his own conservative views are in line with those of Republican voters and even some Democrats in the 12th District, which takes in part of Hillsborough County near Tampa as well as most of Polk County farther inland.

“I think I’ll appeal to a broad base. I firmly do,” Ross said. “I’m not an extremist, I’m not a fanatic. I’ve got kids in public school here and I’m part of this community.”

But to have a shot at succeeding Putnam, Ross almost certainly would have to make it through a primary.

Among his possible opponents is Republican state Sen. Paula Dockery, with whom he says he has been friends for 20 years. “I talked to her three weeks ago and she did express that she was thinking about it, but that she would make her decision in May,” when the state legislative session is scheduled to conclude. Ross noted that he is forging ahead, regardless of Dockery’s decision.

On the Democratic side, usually the underdog in 12th District elections, members of the party establishment have begun rallying behind Edwards. “I wanted to make a strong statement, make it perfectly clear that I’m motivated and I’m ready to roll up my sleeves and work hard starting now to do this,” Edwards told CQ Politics about the early start to her campaign.

Edwards, who describes herself as a political moderate, served in the state legislature for eight years prior to her first election as county elections supervisor in 2000.

Edwards said she expects the Democratic field to become crowded, though. She already faces a comeback bid by Doug Tudor, a Navy veteran who took a bit less than 43 percent in the 2008 House race as the Democratic challenger to Putnam.

Tudor — whose long-shot bid last year was not a high priority for national or state Democratic strategists — contends that his showing was strong, considering that he was vastly outspent by incumbent Putnam.