If the political truism is that "all politics is local," then in Hawaii the corollary is that all local politicians are liberal.

Our state Legislature has only eight Republicans, including just one in the Senate. While Hawaii was slow to take up same-sex marriage, when we got around to it, it was via a special session the Legislature devoted just to passing the law.

Calling something "liberal legislation" is no slight in Hawaii; it is a stamp of approval. The only label better than "liberal" is "liberal progressive."

So in this year’s race for the late Daniel K. Inouye’s Senate seat, Democratic U.S. Sen. Brian Schatz and Democratic U.S. Rep. Colleen Hanabusa are campaigning as bona fide liberals.

Last week, Washington’s National Journal helped with the assurances by rating all members of Congress.

Schatz, along with Chris Murphy, D-Conn. and Chuck Schumer, D-N.Y., all tied as the most liberal members of the Senate. The National Journal rating had them as 89.5 percent more liberal than their colleagues. Not trailing by much was Hawaii’s U.S. Sen. Mazie Hirono, who was 88.2 percent more liberal than her colleagues.

In the House, Hanabusa was rated as more liberal than 73 percent of her 435 fellow representatives. Freshman Hawaii Democratic U.S. Rep. Tulsi Gabbard was rated as 64.3 percent more liberal.

The National Journal report notes that for the past three decades, it has rated members of Congress based on selected roll-call votes from the previous year to see how they compared on an ideological scale.

Neal Milner, University of Hawaii political science professor emeritus, said the scores for Schatz and Hanabusa show that "from a statistical standpoint, the two are so close that it means very little."

The key, however, is that political primaries are a gathering of the faithful and there are bound to be measurements of just how liberal are the credentials of Schatz and Hanabusa.

"Being the most liberal has advantages because people who vote in primaries tend to be more ideological and less centrist than general election voters. In other words, being a liberal — progressive is the term candidates now use — helps in a Democratic primary," said Milner in an email interview.

Two years ago, in a Senate race, former U.S. Rep. Ed Case was chewed up by Hirono over the question of whether Case was liberal enough for Hawaii Democrats.

Case had a liberal rating of 59 percent from the National Journal, but that was sufficiently lower than Hirono’s rating to trigger a rant by political bloggers.

In this election, no one should question that Hanabusa and Schatz are both big enough liberals with voting records that should erase worries that either would suddenly side with the NRA or the Chamber of Commerce.

Failing to find much ideological difference between Schatz and Hanabusa will force voters to search for new reasons to vote for or against them.

Gov. Neil Abercrombie, who appointed Schatz to the vacant Senate seat, has described him as the wave of the future, explaining his action as clearing the way for new blood in the Democratic power structure.

In comparison, Hanabusa who came to office the same year as Schatz, says that her record of accomplishment as a state political leader far outweighs that of Schatz, giving her the credibility needed now.

Neither argument is an easy one for voters to grasp, but it will provide for more of a debate than measuring who is the bigger liberal in Hawaii.

Richard Borreca writes on politics on Sundays, Tuesdays and Fridays. Reach him at rborreca@staradvertiser.com.