Polls show Mitt Romney headed for a blowout victory in the New Hampshire Republican primary. He earns 43 percent in a Suffolk University/7News poll released Wednesday; Ron Paul stands in second with 14 percent; Newt Gingrich is at 9; Jon Huntsman at 7; and Rick Santorum at 6. Indeed, nearly every poll conducted this cycle has shown Romney with a double-digit advantage. Why is Romney so much stronger in the Granite State than in Iowa, where he topped Santorum by only eight votes?

There are two big reasons.

1. New Hampshire is a much better ideological fit for Romney than Iowa.Moderates and liberals made up more than four in 10 New Hampshire Republican primary voters in 2008, while “very conservative” voters accounted for 21 percent of the electorate. Due in part to the fact that non-partisan registrants (known as “undeclared”) can vote alongside registered Republicans. Strong conservatives were among Romney’s worst groups in Iowa on Tuesday – he won 14 percent of their votes compared with 35 percent among moderates and liberal caucus-goers, according to the network entrance poll.

New Hampshire’s conservatives also see Romney differently than those in Iowa. Romney won very conservative voters by a 24-point margin over Sen. John McCain and Mike Huckabee in 2008. A December NBC/Marist poll found Romney performing worse among “very conservative” voters this time around, but he still draws twice as much support as he earned on Tuesday night in Iowa (29 percent).

Similar to very conservative voters, tea party backers in New Hampshire have a much different take on Romney than their Iowa counterparts. While only 19 percent of tea party voters supported Romney on Tuesday, the Suffolk poll finds 45 percent of likely voters who say their values are similar to the tea party currently support Romney.

2. Evangelical Christians also are less dominant in New Hampshire and much more supportive of Romney than in Iowa, where he struggled to court them in both the 2008 and 2012 caucuses. The group made up less than a quarter of New Hampshire primary voters in 2008, compared with 60 percent of Iowa caucus-goers in that year (they made up 57 percent this year). Further, Romney nearly tied Mike Huckabee – an ordained Baptist minister – among evangelicals in 2008, winning 27 percent support among New Hampshire evangelicals. One week earlier in Iowa, the Baptist Minister captured an overwhelming 46 percent of the evangelical vote.

Santorum could be Huckabee’s conservative Catholic analogue, but his very low support in current polls, even among evangelical Christians, shows he has a long way to go. He promises a more populist argument to New Hampshire voters than in Iowa, though with less than a week before voting begins, its unclear whether such a message has time to resonate. He fares slightly worse among voters with less education in the December UNH/Boston Globe poll, and wins 1 percent support among Catholic likely voters.

One big caveat is in order. Even with Romney’s big lead in current polls, New Hampshire voters are known for delivering surprises on primary day. The 2008 Democratic contest where Hillary won despite polls showing Obama ahead is perhaps the most famous, but polls have been shipwrecked by the Granite State many times before. Romney faces challengers from his ideological right (Gingrich and Santorum) as well as those looking to compete for moderates and independents (Huntsman and Paul).

Nevertheless, Romney’s larger-than-20-point lead this close to the primary, especially as 64 percent of voters in the Suffolk University poll say they’re unlikely to change their mind, should give him great confidence heading into next Tuesday.

More from the Post polling team

Sign up for Post polling e-mails

Follow Post polling on Twitter

Like Post Politics on Facebook