The polls have opened statewide for the primary election that's a step leading to a new U.S. senator for Texas.
Republican U.S. Sen. Kay Bailey Hutchison is not seeking another term.
Nine candidates are squaring off for the GOP nomination. If nobody wins a majority in Tuesday's primary, a runoff will be held July 31 between the top two finishers. Two Democrats are seeking Hutchison's seat.
The contest headlines 170 major competitive races statewide. Those include the race to replace the retiring Ron Paul in Congress, and for four new congressional seats the state gained thanks to its booming population.
Voters will also decide today just how conservative the 2013 Texas Legislature will be. Republicans already hold large majorities in both the House and Senate and will likely remain in power in 2013. But redistricting, retirement and ambition for new office have caused some blistering campaigns, particularly between some GOP colleagues.
The face of the Texas Board of Education could also change with all 15 spots up for re-election. The positions are among the races on the ballot in today's Texas primary. Currently, there are four Democrats and 11 Republicans on the board.
Mitt Romney is poised to clinch the Republican presidential nomination after Tuesday's Texas GOP primary, a largely uncontested election that will formalize the former Massachusetts governor's status as President Barack Obama's general election challenger.
While Romney's nomination has been virtually assured for a month, the day marks the culmination of several years of work, dating back to his unsuccessful 2008 effort, and perhaps far earlier.
Romney told reporters he was "looking forward to the good news."
The polls are open until 7 p.m. Tuesday. The general election is Nov. 6.
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