KING 5 poll: Who gives Obama a tougher challenge in Washington state?

A new KING 5 poll finds Republican Mitt Romney would give President Obama a stiffer challenge in Washington state than Newt Gingrich.
While Gingrich is now leading the Republican race in many polls, he doesn’t fair as well in a head-to-head race against Obama in our new SurveyUSA poll of likely voters in Washington state.
The poll finds with either Republican candidate, Obama would carry the state if the election were held today:
Obama/Romney matchup: Obama 49%; Romney 41%; Undecided 10%
Obama/Gingrich mathup: Obama 56%; Gingrich 37%; Undecided 8%.
The poll of 549 likely voters has a margin of +/-4.2%.
The poll finds Gingrich does not hold as many Republican voters as Romney (holding 76% vs. Romney’s 85%). Gingrich also does worse among independents (35% vs. 39% for Romney).