Bush on Trump: Time to 'punch him back in the nose'
But, given her not-so-veiled shots at Donald Trump during her GOP response to the State of the Union, it's not surprising she chose to throw her influence behind one of the real-estate mogul's rivals.
Trump has been furious for days over Cruz's attacks slamming him as a NY liberal disguised as a Republican.
John Kasich is in fourth at 10 percent support, followed by former Florida Gov. Jeb Bush and retired neurosurgeon Ben Carson, tied with 7 percent support each.
Haley's endorsement gave Rubio, 44, a valuable ally to try to sway voters in SC, the third contest after Iowa and New Hampshire to pick a party nominee for the November election to succeed Democratic President Barack Obama. Rubio also has been endorsed by two other members of the congressional delegation in South Carolina: Rep. Trey Gowdy, R-Spartanburg, and Sen. "Like a freight train barrelling through signals with his horn on full blast, Trump heads down the track towards a possible nomination", said Tim Malloy, assistant director of the Quinnipiac University Poll.
Cruz said on Wednesday that Trump's campaign sent him a cease-and-desist letter over the ads, demanding he take down one airing in SC, which includes a years-old clip of Trump stating his then support for abortion rights.
"When people chose somebody the first time, the rest of the campaign is really spent deciding if they should change their mind", said Jon Gray of Strategy Research.
Haley said she wanted to endorse a president who "would have the back of our military veterans and those in active duty", and who is "all about term limits in D.C". Similarly, Rubio and Bush are splitting the moderate vote.
"They're a repressive regime", Rubio said. Cruz has questioned Trump's commitment to the Second Amendment, as well as his opposition to abortion.
"Trust me, she's a great person". He denied being involved with anything untoward and called for anyone with evidence to come forward. "If you want to file a lawsuit... file the lawsuit".
Trump has repeatedly advocated enhanced interrogation techniques for foreign prisoners, and he said again Wednesday he would "absolutely" allow waterboarding, which simulates the feeling of drowning.
"In many parts of society today, whether in popular culture, academia, the media or politics, there's a tendency to falsely equate noise with results", she said.