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 RubioAt CPAC, Trump lashes out at media Conquering Trump returns to conservative summit Rubio brushes off demonstrator asking about town halls 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 PaulConquering Trump returns to conservative summit Rand Paul rejects label of 'Trump's most loyal stooge' GOP healthcare plans push health savings account expansion MORE (R-Ky.), 11 percent for former Florida Gov. Jeb Bush (R) and Rep. Paul RyanPaul RyanIf Democrats want to take back the White House start now GOP grapples with how to handle town halls Leaked ObamaCare bill would defund Planned Parenthood 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.