WASHINGTON — Just like that, Hawaii has a national horse race.

Gov. Linda Lingle‘s long-anticipated announcement on Tuesday that she will run for the U.S. Senate has political trackers across the country looking to the Pacific.

Republicans need to take back four Democratic seats in 2012 to regain the Senate majority. And while Hawaii tends to vote predictably and overwhelmingly for Democrats, Lingle is one of the rare Republicans who has successfully — and repeatedly — won elections in the Islands.

Lingle is expected to cruise easily to the general election, where she will likely face either Congresswoman Mazie Hirono or former Congressman Ed Case, who are vying for the Democratic nomination. Democratic Sen. Daniel Akaka announced he would not seek re-election earlier this year.

As The Washington Post pointed out, Lingle’s past victories indicate that she can appeal to moderate Democrats — one reason why Democrats were so quick to play up Lingle’s conservative roots amid news of her Senate candidacy.

Lingle’s ability to win in a solidly blue state is not lost on national political analysts who identify Lingle as a top GOP recruit who, as the National Journal put it, is turning Hawaii into “an unlikely Senate battleground.”

Just the fact that she’s running is seen as a coup for Republicans. The GOP donations that will flood Lingle’s campaign coffers will likely make the race more expensive for Democrats — which could, in turn, stymie the cashflow to Democrats in other battleground states. Democrats are already trying to defend twice as many Senate seats as Republicans in 2012.

Republicans could make strides in Florida, Missouri, Montana, Nebraska, North Dakota, Ohio, Virginia, West Virginia and Wisconsin, among other states.

• The Los Angeles Times reports that Lingle is giving Republicans “one of their best opportunities” to take back the Senate.

• The Hill calls Lingle “the only Republican” who could have made this race competitive.

• Roll Call, another Capitol Hill newspaper, describes the Hawaii Senate race as a must-watch in 2012, but also characterizes it as “likely Democratic.”

And yet Democrats may still be buoyed by the fact that Honolulu-born Barack Obama’s name will be at the top of the ticket.

One astute observation from The Washington Post: “Hawaii isn’t considered one of (Republicans’) top pickups, so if they win… it will likely be part of a big GOP wave.”