From the end of World War II through the fall of Saigon, no sitting or former governor was elected president of the United States. But beginning with 1976, and in the two national elections since, one or both parties have nominated for president a former governor, and in the last 12 years only former governors -- Jimmy Carter and Ronald Reagan -- have won the White House.

Now Massachusetts Gov. Michael Dukakis leads the Democratic primary field in New Hampshire and could possibly even win the Iowa caucuses on Feb. 8. Let it be noted that back-to-back victories in those first two states by any candidate would immediately elevate that winner from Front-Runner to Prohibitive Favorite. Still the question remains: Why have governors so recently become such hot properties in our presidential politics?

The reasons for the political ascendancy of governors are basically geographical-historical, occupational and political. First the geographical-historical: no state capital is in Washington, D.C., which has been, of course, the dateline for so many national disappointments from the Tet offensive through the pardon of a resigned president and double-digit inflation. A Washington office and daytime phone number have not lately been advantages in securing a party nomination. The governor of a state, by definition, is not part of the Washington problem, whether that "problem" be arrogance, chaos, deadlock, ineptitude or sleaze.

National politics in Washington became during the '60s and '70s the battleground for a polarizing clash over personal and traditional values. Equating restraint with repression, advocates of repeal found support in the national Democratic Party while the Republicans welcomed the resistance. Moral relativism failed to win majority support because most Americans remain, in the insightful phrase of William Galston, "tolerant traditionalists" who affirm the values of family, work and faith but who oppose all those committed to using state power to impose their own special views on society.

Because most of the fights have been at the federal level, governors have been able to avoid many of those thorny and sticky moral-political issues and the inevitable demonizing that attends them.

The successful governor, unlike a national legislator, can be a nonideological performer, someone who has actually balanced budgets and who can point to a real record of fiscal responsibility. Such a governor can also trumpet actual, visible results of his term in office -- of schools built, roads opened, communities physically changed. Politically, the governor can be simultaneously the Effective Outsider and the Successful Doer.

The Democratic governor enjoys a significant advantage over his party rivals from Washington, where for 16 of the past 20 years the Republicans have won and wielded executive power. Much of the rhetoric of the national Democratic legislators comes across as so relentlessly critical as to be negative and to recall Irish playwright Brendan Behan's comparison of critics to eunuchs in a harem: "They're there every night. They watch and listen every night. They see how it should be done. They simply can't do it themselves."

As Ronald Reagan proved in the 1980 campaign, a successful record as governor can persuasively rebut charges that one is an ideologue. Whenever the Carter campaign revealed some earlier right-wing rambling of the Gipper, the Reagan camp would remind voters that their man had inherited a billion-dollar deficit and left his state -- with the sixth largest gross national product in the world -- with a budget surplus and a citizenry both happy and healthy.

From Vietnam to Central America and the Persian Gulf, our politics has featured bitter partisanship over foreign policy. Again governors have the opportunity to remain silent during many of these brawls and then to choose which foreign policy issues to raise and which to avoid. A governor on foreign policy has essentially a clean slate. (However, Dukakis may already have squandered this edge by citing as a curious foreign policy credential his refusal to approve sending his home state National Guard on maneuvers to Honduras.)

Sitting governors, because their administrations do build roads and regulate commerce, also have available to them sources of campaign funds motivated probably less by conviction than by good business. Asphalt and horse racing are notoriously nonideological.

Of course, any sitting governor who is a candidate for president lives daily with the risk of embarrassment by opponents in the legislature or by any one of his hundreds of "appointees" being found with his hand in the public's petty cash. But up to now, the fact remains that being governor carries large advantages for a presidential candidate.