WASHINGTON (Reuters) – The campaign of Republican presidential candidate Mitt Romney on Thursday launched a fierce attack on Newt Gingrich, who shot to double-digit leads over Romney in opinion polls of several states.

Romney’s campaign unleashed two respected conservative Republicans – former White House chief of staff John Sununu and former Senator Jim Talent – to question Gingrich’s ability to take on President Barack Obama.

Talent, a congressman in the 1990s when Gingrich was Speaker of the U.S. House of Representatives, shot the strongest salvo by saying a Gingrich nomination would hand Obama the election next year.

“If the nominee is Newt Gingrich then the election is going to be about the Republican nominee – which is exactly what the Democrats want,” Talent said on a conference call with reporters.

He said if Romney was the nominee the race would not be focused on him but on Obama’s record and the Republican would have a good chance of winning.

“If they can make it about the Republican nominee then the president is going to win and that’s exactly why they’re pursuing the strategy they’re pursuing now – attacking Mitt Romney in advertisements because they’re hoping Governor Romney is not going to be the nominee,” Talent said.

A series of new polls showed Gingrich has been gaining ground and jumped to double-digit leads over former Massachusetts Governor Romney in several states including some of the first voting states for the Republican primary.