For 40 years, the Fort Worth seat has swung power and politics in the Texas Senate.From the 1972 election of Republican trailblazer Betty Andujar to the 2008 upset victory by Democrat Wendy Davis, Fort Worth and Tarrant County have taken a strong hand in shaping both the direction of the Senate and the future of Texas.In an age when districts are drawn for one-sided elections, somehow the Fort Worth election is always close.If Davis has decided to run for higher office — as she has signaled she might, based on national fundraising — then Fort Worth, Arlington and south Tarrant County will face their own decision.With only seven months before the party primaries, the Senate District 10 seat would be open with no incumbent running for the first time since state Sen. Mike Moncrief chose to come home to be Fort Worth’s mayor.As the state and nation talk about Davis and her prospects for higher office, Tarrant County leaders also must talk about our seat in the Texas Senate.This is typically no job for a beginner.Moncrief, a Democrat, came to the Senate after 12 years as Tarrant County judge and took a strong hand in shaping bipartisan healthcare laws under Gov. George W. Bush.His successor, Republican state Sen. Kim Brimer, moved to Fort Worth and into the Senate after representing Arlington and south Tarrant County for 14 years in the House. He had earned honorable mention on Texas Monthly’s “Best Legislators” list for his work on taxes and economic development.Davis had helped guide downtown growth and south side redevelopment during her 10 years on the Fort Worth City Council.If Tarrant County is going to have an open seat for a state senator, the time to talk about that is near.Republicans have a slight edge in District 10, but the district has changed since Davis won it five years ago.Much of the district is dominated by straight-ticket Democratic voters in north, south and southeast Fort Worth, but some of the heaviest voting also comes from predominantly Republican boxes in southwest Fort Worth, Benbrook, southwest Arlington and Mansfield.Those Republican boxes in southwest Fort Worth near Crowley and in Mansfield have attracted more Democratic voters each cycle. The district is no longer a slam-dunk for a Republican, although it still includes conservative boxes in the Northeast Tarrant County cities of Bedford, Colleyville and Southlake.Davis won by drawing crossover Mitt Romney voters in those districts and also by winning support from educators, particularly in the university communities around Texas Christian University, Texas Wesleyan University and the University of Texas at Arlington.In an off-cycle election with Sen. John Cornyn’s seat atop the ballot instead of a presidential campaign, the odds might favor a Republican.The 2014 campaign themes will revolve around President Obama, Gov. Rick Perry and the Republicans controlling the Texas House and Senate.In an off-cycle election with a Democrat in the White House, a Republican would typically criticize Washington. In turn, Davis or another Democrat would criticize Republican leaders in Austin.The swing district gives Fort Worth a powerful role in the Senate. Since a two-thirds vote is traditionally required to debate most bills, Davis often was one of the Democratic holdouts who could either consent to or stymie debate.Some of the Republican candidates running for lieutenant governor have said they want to change that rule no matter how the next election turns out, but that is yet to be seen.The Fort Worth Senate seat is not only one of the most important in the Senate but also one of the most expensive. Spending by both sides passed $5.5 million in 2012.No matter whether or where Davis chooses to run in 2014, her next campaign will cost plenty of money. Three Republicans have filed for the Senate seat so far, with more anticipated for the primary March 4.If new leaders must emerge, time is short.