There's a chance San Antonio Democrat Julian Castro could use a little used loophole in Texas Election Code to run for both president and John Cornyn's U.S. Senate seat at the same time.
The "LBJ Law" was put in place in 1959 as an exemption to allow then Senate Majority Leader Lyndon B. Johnson to seek re-election while also running for president or vice president.
“The law was designed specifically for LBJ, it's so tailored to his circumstances at that point, I don't know if it would have an impact now,” says Dr. Brandon Rottinghaus, political science professor at University of Houston.
Sen. Lloyd Bentsen used the exemption again in 1988 when he sought re-election while running as VP alongside Michael Dukakis, but Rottinghaus believes voters are much savvier these days.
“From a political standpoint it's going to look like you're double-dipping and people don't like you're taking advantage of this law which is an usual loophole. It's also just from a practical point of view a complication,” he says.
“You can't be two places at once and I think voters kind of get a sense that you're not in to one or the other, and may take it out on you.”
Beto O'Rourke would have been afforded the same option, but already said this week he would not run for U.S. Senate. Castro so far has said he won't run against Cornyn either.