Clinton's approval rating is at 50 percent with 43 percent disapproving, strong marks for any politician in the state — especially a Democrat. In hypothetical matchups, she leads Sen. Marco RubioMarco RubioGOP senator: Trump budget 'dead on arrival' China’s 'ban' on North Korean coal isn't the tough stance it seems Rubio moves to name street outside Russian embassy after slain opposition leader MORE (R-Fla.) 46 percent to 45 percent, and New Jersey Gov. Chris Christie (R) 45 to 43.

The poll is the latest evidence that Clinton would start off the 2016 presidential race with an immense amount of goodwill, should she decide to run, as well as a sign that Texas's shifting demographics could transform it into a swing state.

Clinton's edge increases considerably when she is paired against Texas Gov. Rick Perry (R): She'd lead the former presidential candidate by 50 to 42 percent. Seven in 10 voters don't want Perry to run for president again.

Rubio leads a pack of potential GOP presidential primary candidates with 21 percent support, followed by 14 percent for former Arkansas Gov. Mike Huckabee (R), 13 percent for Sen. Rand PaulRand PaulSenate GOP to huddle Wednesday on ObamaCare repeal strategy Cruz, Lee, Paul demand 'full repeal' of ObamaCare Top House conservatives won't back draft ObamaCare replacement MORE (R-Ky.), 11 percent for former Florida Gov. Jeb Bush (R) and Rep. Paul RyanPaul RyanRyan won’t say if he has seen evidence of contact between Trump campaign, Russia The Hill's 12:30 Report GOP leader: Leaked ObamaCare replacement 'no longer' viable MORE (R-Wis.), 9 percent for Christie, 4 percent for Perry and Louisiana Gov. Bobby Jindal (R), and 2 percent for New Mexico Gov. Susana Martinez (R).

The automated poll of 500 Texas voters and an oversample of 400 usual Republican primary voters was conducted from Jan. 24-27 and has a margin of error of plus or minus 4.4 percentage points, with a 4.9 percentage point margin of error for the GOP primary numbers.