ESPAÑOLA, N.M. — In the early days of the presidential campaign, Senator John McCain seemed to be in a good position to win support among Hispanic voters. He had sponsored legislation for comprehensive immigration overhaul in Congress, made a point of speaking warmly about the contributions of immigrants and was popular among Latinos in Arizona, his home state, which borders three battleground states here in the Southwest: New Mexico, Colorado and Nevada.

But less than two weeks before Election Day, those advantages appear to have evaporated. Recent Gallup polls show Mr. McCain running far behind Senator Barack Obama among Hispanic voters nationwide, only 26 percent of whom favor the Republican. The possibility that Mr. McCain can duplicate George W. Bush’s performance among Latinos in 2004, when Republicans won 44 percent of the vote, now seems remote.

Both candidates are spending heavily on Spanish-language advertising, and continue to schedule campaign events to focus on the fast-growing Hispanic vote. Last month, Mr. McCain held a town-hall-style meeting at a Puerto Rican community center in central Florida; a few days later, Mr. Obama, of Illinois, came to this heavily Hispanic city of 9,600 people for a rally at a plaza that dates to Spanish colonial times.

In an echo of his overall slide in the polls, some of the issues that have hampered Mr. McCain’s candidacy turn out to have had an even greater impact on the Hispanic population. Latinos cite the crisis in the economy as their biggest concern, trumping immigration and the social conservatism that Republicans thought would help expand Mr. McCain’s appeal among religious, family-oriented Hispanic voters.