THE BURNED OVER DISTRICT

And the Republican Party is the pooch. Their greatest fears are in sections of the West where ugly conservatism has held sway for numerous election cycles up to now.

Republicans in Western states fear that Donald J. Trump could imperil their party for years to come in the country’s fastest-growing region as he repels a generation of Hispanics, Asians and younger voters who have been altering the electoral map.

Mr. Trump, with his insult-laden, culturally insensitive style of campaigning, is providing fuel for the demographic trends that are already reshaping the political composition of this once-heavily Republican territory. And now many Republicans are contemplating the possibility that states like Colorado or Nevada could soon become the next California: once competitive but now unwinnable in presidential contests.

In few places are the party’s woes over their nominee more immediate than here in Arizona, a state that has voted for the Democratic presidential candidate only once in the last 68 years.

Recent polls show Hillary Clinton is close to tying Mr. Trump here. And her campaign has responded by teaming up with local Democrats on a statewide get-out-the-vote operation, which has grown to 160 staff members across 20 offices.

While flipping Arizona has been a Democratic fantasy for years — and one that Clinton supporters acknowledge remains quite difficult — their efforts to register and recruit voters are part of a longer-term plan to capitalize on the Republican Party’s vulnerabilities with younger and minority voters.

Nonwhites are growing as a share of the electorate faster in the West than they are elsewhere. For the first time, minorities in 2012 accounted for at least 30 percent of the eligible voting population in Arizona, Nevada and Alaska — all states where Republicans currently hold top statewide offices. Colorado, where Mrs. Clinton’s campaign is so confident of a victory now that it has has no plans to buy advertising time through Election Day, is also approaching 30 percent.

The demographics were already daunting. But many Republicans now say Mr. Trump is only accelerating the flight of minority voters to the Democratic Party, like dry underbrush feeds an Arizona wildfire.

Some GOPers are saying things will be OK if you keep your distance from Trump. But the Great Orange Fungus is like a nuclear bomb, he can kill your election chances far from the immediate blast area.