The explanation is simple: While Monday's massive marches in several U.S. cities were a demonstration of strength, the boycott of American products called by some of its organizers was a stupid idea. It gave anti-immigration groups (or anti-illegal-immigration groups, as they call themselves) ammunition to portray the peaceful demonstrators waving American flags as a hostile, potentially dangerous crowd.

Even Republican Sen. Mel Martinez of Florida, co-sponsor of a more benign immigration bill than the one approved by the House of Representatives in December, says that the "day without immigrants" was "largely counterproductive." Boycotts "send the wrong message" to undecided legislators in Congress, he says.

But here's the twist: Down the road, while most of the estimated 30 million anti-immigration voters will shift their attention to other issues, such as the economy, oil prices or Iraq, most of the estimated 10 million U.S. Hispanic registered voters will remember for a long time which political party sided with them on the immigration issue and will vote accordingly for years to come.

Call it the "Pete Wilson effect," if you want. Remember Pete Wilson? He was the former mayor of San Diego who came from way behind in the polls to win the California governorship in 1994 by campaigning on an anti-illegal-immigration platform. At first, his support for Proposition 187 curtailing undocumented workers' access to schools and hospitals helped him win big, but in the long run it turned out to be a disaster for his party.

After Wilson's victory, an estimated 1 million Latinos in California became U.S. citizens, registered to vote and massively cast their ballots against the Republican Party in the 1996 presidential elections and thereafter. It may be no coincidence that one of the main slogans of Monday's marches was "Hoy marchamos, manana votamos." ("Today we march, tomorrow we'll vote.")

"Since 1996, there have been eight elections in California, and the Democrats have easily won seven of them," says Sergio Bendixen, a leading U.S. Hispanic population pollster for the Democratic Party. "California has become the bluest state in the political map, in great part thanks to Wilson's stands in the 1990s."

In fact, advocates of draconian anti-immigration measures, such as declaring all undocumented workers criminals, don't represent a majority view in America. A new AP-Ipsos poll shows that 56 percent of Americans favor allowing undocumented immigrants to apply for legal, temporary worker status. In addition, nearly 50 percent say undocumented workers "mostly make a contribution" to American society, while 42 percent say they are "mostly a drain."

Granted, if you watch most cable television and listen to talk radio, you may get the opposite idea (never mind the hypocrisy that many of the anti-immigration guests and callers on radio programs love the fact that they are paying less for their undocumented gardeners, nannies and personal trainers).

Xenophobic populists such as CNN's Lou Dobbs and Fox News' Bill O'Reilly milked the boycott to the hilt, and their followers loved it.

(Dobbs, by the way, is crossing the boundaries of legitimate editorializing with what comes across as a blatant contempt for Hispanics. On Monday, he introduced his own correspondent, Juan Carlos Lopez, with such an exaggerated mispronunciation - "One Carlos Lopeeeez" - that it was hard not to perceive an intentional racial slur by somebody whose job requires to at least try to pronounce people's names properly. Lopez, by the way, is the most common Hispanic last name.)

My conclusion: While there is an immigration crisis that requires prompt solutions, one has to wonder whether this should be the top issue on the agenda of a country with a low 4.7 percent unemployment rate, or whether it's a smoke screen used by some right-wing Republicans in the House to keep us from focusing in November elections on the Iraq war or $3-a-gallon gasoline.

If it's the latter, they may succeed, but it will be a short-lived, pyrrhic victory. The let's-seal-the-border crowd will soon find another cause and forget about this whole issue. Hispanics won't.

Andres Oppenheimer is a Latin America correspondent for the Miami Herald, 1 Herald Plaza, Miami, Fla. 33132; e-mail: aoppenheimer@miamiherald.com.