-- If Texas were not in the Union, the Democrats would currently have a filibuster-proof majority in the Senate -- or at least they would once Al Franken gets seated. This is because, in a 98-seat Senate, only 59 votes would be required to break a filibuster.
-- If Texas were not in the Union, the Republicans would operate from a significantly weakened position in the House, since the net 8-vote advantage their congressional delegation gives them in the state (they have 20 seats to the Democrats' 12) is by far their largest.
-- If Texas were not in the Union, George W. Bush would never have become President in 2000 -- not because he'd be constitutionally ineligible (Bush, despite his Texas twang, was born in posh New Haven, Connecticut). Rather, he wouldn't have had enough Electoral Votes to defeat Al Gore.
-- If Texas were not in the Union, Barack Obama would have won the Electoral College 389-147 instead of 365-173 (note that there are two fewer votes total, because there would be two fewer Senators). The vast majority of Texas' electoral votes would be redistributed to lib'rul states like California (which would go from having 55 electoral votes to 59) and New York (34 rather than 31)
So, let's get behind this Texas Secession business. Governor Rick Perry, do it. Come on. Don't be scared.