Cheney calls Palin's selection as 2008 US VP candidate 'a mistake'

* McCain picked Palin as running mate, lost to Obama

* Cheney says he likes Palin, but she was inexperienced

* Says Palin didn't pass test of being ready to 'take over'

WASHINGTON, July 29 (Reuters) - Former U.S. Vice President Dick Cheney said in remarks aired on Sunday that 2008 Republican presidential candidate John McCain's selection of Sarah Palin as his vice presidential running mate was "a mistake" because of her inexperience.

Cheney said in an interview with ABC News that the main criterion for anyone being considered as a potential future vice president "has to be: Is this person capable of being the president of the United States."

Cheney, a prominent conservative who remains an influential figure in Republican circles, said he personally likes Palin, who was a first-term governor of Alaska when Arizona Senator McCain picked her as his running mate four years ago.

"I like Governor Palin. I've met her. I know her. She was an attractive candidate," Cheney said.

"But based on her background - she had only been governor for what, two years? I don't think she passed that test ... of being ready to take over. And I think that was a - a mistake," Cheney added.

McCain and Palin lost to the Democratic ticket of Barack Obama and running mate Joe Biden.

Cheney cited his experience in leading the search for running mates for two Republican presidential candidates - incumbent President Gerald Ford in 1976 and George W. Bush in 2000. The latter ended with Cheney himself being chosen as Bush's running mate, and he served as vice president from 2001 to 2009.

Before being elected vice president, Cheney had served as U.S. defense secretary, a White House official, a congressman and a business executive.

Cheney, 71, underwent heart transplant surgery in March in Virginia. Cheney, who has suffered five heart attacks, had been on the cardiac transplant list for more than 20 months before he received the heart from an anonymous donor.

On July 12, Cheney hosted a fundraising event to add to Republican presidential candidate Mitt Romney's brimming campaign coffers.

Palin, the first woman ever to be chosen as the Republican vice presidential candidate, was an unconventional selection in that she was a novice on the U.S. national political scene with relatively little experience in public office.

Palin's selection initially energized McCain's campaign, but she committed a series of gaffes and there was tension between her camp and McCain's advisers behind the scenes.

Palin announced last October she would not seek the Republican U.S. presidential nomination in 2012. Palin cited family considerations as playing a major factor in her decision. She has felt the U.S. news media has gone too far in covering her family, such as the drama involving her daughter Bristol's tempestuous relationship with the father of her child, Levi Johnston.

She made clear she would turn her attention toward recreating a role she carved out for herself in the 2010 congressional elections, helping elect conservatives in tune with the conservative Tea Party movement to Congress, state governorships and the White House.

Palin and McCain endorsed rival candidates in the Indiana Republican Senate primary this year.