Arizona's Republican Sen. John McCain -- regardless of the Democratic candidate -- presents voters with a chance to make a bright-line decision.

The poisonous political divisions in Washington have made it difficult for either party to reach the compromises that the Constitution's separation-of-powers doctrine forces. But while political extremes battle to gridlock, the problems do not go away and only grow more serious.

McCain commands the respect necessary to reach across the aisle on serious issues.

As a Navy aviator and prisoner of war who has looked death in the face, he's tough enough -- with a salty, lifelong streak of maverick -- to buck his own party when necessary. And he's smart enough to know that compromise often is the best solution that either party is going to get.

The irony is that because he is all of those things, he is unacceptable to some of his party's more conservative and intolerant elements.

Presidential candidates speak in absolutes -- that they'll do this or that. On the campaign trail, they can't take the time to add "... if I can get Congress to go along with me." Still, those promises are worth examining because they indicate a candidate's core beliefs.

McCain says that, if elected president, he will:

Pursue the opportunity for victory in Iraq, "strengthen our hand against Islamic extremists" and make the nation more secure. Whether he would have launched an invasion in the first place is not a material question. But had he been president, it is likely that he would have insisted on an initial troop level that would have been able to secure the country. The results of the choice not to do that are clear.

Build a national healthcare market where insurance is more available and assist those who need help in obtaining private insurance.

Veto wasteful, pork-barrel spending bills "every time." He is correct when he says that "excessive borrowing and deficit spending in Washington must stop."

Modernize Social Security, Medicare and Medicaid. McCain's policy statements say that without "comprehensive bipartisan reform ... the nation will be unable to meet the challenges of providing vital medical and social security assistance to future generations." Note the use of the word bipartisan.

Secure the nation's borders -- but recognize that such a step is more effective if it is coupled with building strong allies in Mexico and Latin America and encouraging pro-growth policies that allow U.S. businesses to hire and pay the best, a flexible labor market that provides Americans and immigrants with opportunity, and assimilation of the immigrant population.

Provide for service members and their families while they serve; assist those returning from combat, including providing them with adequate healthcare; and honor and remember those who have died in service to their country.

Defend Second Amendment rights, which should please many Texas Republicans.

As president, would he be able to deliver on those promises? Some yes, others in part, and some no.

But where he stands is clear and consistent. And come November, the voters will be able to choose between candidates with clear agendas and policies.

The Star-Telegram Editorial Board recommends John McCain in the Republican primary for president.