Phoenix, Ariz. — The first political axiom of the Rocky Mountain West: People out here vote Republican for president. Could a native son like Colorado Sen. Gary Hart change that pattern?
It's a slippery speculation so soon in the race, but politicians here agree that Senator Hart would certainly fare better in the West than his chief Democratic contender, Walter F. Mondale.
And in practical terms, the Coloradan - should he win the Democratic nomination - would at least force the Reagan campaign to spend time and money ensuring the President's grip on the Rocky Mountain states. Against the other Democratic hopefuls, most consider the Rockies uncontested Reagan country whose electoral votes the President can take nearly for granted.
''The solid South has given way to the monolithic West in national politics, '' says Arizona Gov. Bruce Babbitt. Whereas the South has traditionally been a Democratic bastion, of course, the West is a Republican stronghold.
But Democrats - of the right sort - can succeed out here.
Paradoxically, voters in the Rockies seem to prefer Democrats as governors. Governor Babbitt and the governors of the other six Rocky Mountain states and Idaho are all Democrats.
At other levels of government, voters routinely run roughshod over party lines.
''There is a fierce streak of political independence,'' says Tucson Mayor Lewis Murphy, a Republican serving his 13th year in the heart of the district that elected liberal Democrat Morris K. Udall to the United States Congress. ''People vote for people . . . by name identification, rather than following party labels.''
Eric Sondermann, a Denver media consultant and former aide to Colorado Gov. Richard Lamm (D), sees the same pattern. ''Colorado tends to favor strong personalities'' over a politician's liberal or conservative stripes, he says, ''as long as they have an independent streak.''
The Democrats who thrive in the Rockies are a different breed from the garden variety grown east of there.
Although Hart is seen as more liberal than the quintessential Rocky Mountain Democrat, according to Mr. Sondermann, part of Hart's appeal in Colorado is his image as an original thinker who questions the party dogma.
Earl deBerge, research director of the Rocky Mountain Poll in Phoenix, says Hart is the right blend of ''conservatism and populism and traditional Democratic liberalism'' to suit the tastes of Western Democrats.
Democrats here are more conservative than most. Indeed, Governor Babbitt's popularity in Arizona soared last summer when he called out the National Guard to quell violence among striking copper miners. Colorado Governor Lamm has angered many Hispanics in his state because of his outspoken concern for limiting immigration.
Both stances cut against the traditional Democratic grain.
Babbitt describes Rocky Mountain Democrats as fiscal conservatives, liberals on civil rights, strong environmentalists, and ''a little bit Southern on defense'' - that is, they favor a strong military.
''A lot of politicians,'' he says, and he includes himself, ''are trying to reconcile this fiscal conservatism with the traditional values of the Democratic Party.''
There is a populist grain among Westerners that rejects established institutions and organizations, especially those perceived to come from the jaded East.
Political parties are one. Unions are another. For example, although Arizona is roughly half Democratic, labor unions continue to lose what little ground they ever held here. The state chief of the AFL-CIO, Darwin Aycock, laments, ''Arizona is to labor what Mississippi was to civil rights.''
Unions, an observer notes, are seen here as oppressive institutions from out of town.
''There is a Western kind of world view that is, superficially at least, antigovernment,'' Babbitt says. But under that veneer of rugged individualism, he adds, Westerners are ''enormously practical.''
For example, he says, Westerners will reject land-use plans, perceived as the edicts of bureaucrats and professors. Yet Arizonans have adopted what is by far the nation's most ''Draconian'' water law. Water conservation here is a tangible need, not a philosophical issue.
However, both Phoenix Mayor Terry Goddard and Denver Mayor Federico Pena were elected recently with strong quality-of-life platforms.
The political extremes on both right and left have been tempered in the West by the influx of migrants in recent decades. The newcomers are generally young, affluent, environmentally conscious, and somewhat entrepreneurial and venturesome. So the independent streak still runs strong.
Mr. Mondale is not expected to run nearly as well in this anti-institutional crowd as Hart.
''Walter Mondale would lose the West uncontested,'' Sondermann says. ''That's definitely not true with Gary Hart.''
The Rockies are not decisive in presidential races. The seven Rocky Mountain states - Arizona, New Mexico, Colorado, Utah, Nevada, Wyoming, and Montana - account for a mere 36 of nation's 372 electoral votes. Some of them, like Utah, are considered beyond the reach of any Democratic presidential candidate, so even to make Mr. Reagan fight for them would be an extra boost.
''We (Democrats) have not tested the West with a candidate that would really appeal to the West,'' says Terry Brazy, a Washington lobbyist and former aide to Congressman Udall. ''Gary Hart upsets the whole Republican equation.''