With the war in Iraq politically on the backburner, illegal immigration is heating up as a campaign issue. The public wants action, and the candidates are scrambling to react.

Sen. Hillary Clinton’s sure nomination was first questioned when she flubbed an easy debate question about driver’s licenses for illegal aliens.

Sen. John McCain’s recovery took off when he backed away from his support of immigration reform that did not first ensure the closure of the border.

Former Mayor Rudy Giuliani is no longer for “sanctuary cities” that shield illegal aliens from arrest. Like former Gov. Mike Huckabee, he’s now a born-again opponent of illegal immigration.

Former Gov. Mitt Romney assures us that some illegal aliens can be deported within 90 days after he’s elected.

Sen. Barack Obama may talk of “change,” but his relative fuzziness about illegal immigration can’t last forever, and at some point he will have to offer more specific proposals.

Some time ago, supporters of open borders lost the debate. The majority of Americans want them closed — now! They ignore the tired slurs like “anti-immigrant,” “racist,” “protectionist” and “nativist.” And noisy May Day parades with Mexican flags and heated rhetoric from the National Council of La Raza (“The Race”) only turn more people off.

It doesn’t do any good, either, for a Mexico City functionary to cry about how mean we are to want a secure border with Mexico. Most Americans also tuned that out long ago.

They know instead that Mexico cares mostly about sending north those it won’t or can’t feed and house — so it can skim off from them billions in remittances once they arrive in the United States.

Mexico City, of course, could reform the country’s laws and economy whenever it wants. But it changes only enough to draw in tourists or Americans looking to buy vacation homes, not to better the lives of millions of its mestizo poor in the heartland.

The spin masters may think illegal immigration is an issue that pits conservative Republicans against liberal Democrats. But it doesn’t always.

Nowadays, worry about illegal immigration is just as likely to mean that African-Americans are terrified of racist alien gangs in Los Angeles. Asian-Americans are frustrated that their relatives with college degrees wait years to emigrate legally, while thousands without high-school diplomas to the south simply break the law to enter the United States.

And many Mexican-Americans are probably tired of being expected to defend the indefensible of foreign nationals breaking immigration laws simply because they may share an ethnic heritage with illegal aliens.

To the extent Democratic candidates ignore illegal immigration, or demonize those who worry over hundreds of thousands of new illegal aliens each year, or talk of guest workers and amnesty before they mention closing the borders, it is a losing issue that could alienate millions of voters.

Democratic candidates can’t really claim that redneck racists are rushing to the border to clash with poor campesinos just crossing to better their lives, because many poor Democrats also resent how illegal labor drives down their own wages. It is mostly the American poor and middle class who worry about the sudden influx of thousands who don’t speak English and often need public assistance.

But the Republican candidates have to watch it, too. If blanket amnesty is a losing issue, so also is mass deportation — the practicality and morality of which are rarely considered by those rightly calling for an end to illegal immigration. Busing every illegal alien back to Mexico right now might resemble the past messy partition of India and Pakistan, and reopen the issue in a way that Democrats can legitimately exploit.

What then might an astute candidate advocate?

Close the border now through fencing, more agents, employer sanctions, enforcement of the law and verifiable identification. Restore faith in the melting pot by insisting that new legal arrivals learn English and the customs and protocols of the United States.

Explain to the Mexican and Central American governments that using the United States to avoid addressing internal problems — while making easy dollars off the backs of their own expatriate laborers — is over.

Finally, deport aliens who have broken the law, are not working or have just arrived. Some illegal aliens will not like the new atmosphere of tough enforcement and will voluntarily go back home. Others may have criminal records or no history of employment and should leave as well.

But many millions of law-abiding, employed illegal aliens of long residence will wish to stay. We should allow these to remain in the United States while they apply for citizenship — if they are willing to learn promptly our language and customs.

Republican candidates must risk angering their base by ruling out mass deportation. Democrats should support closing the border tightly and quickly — and not cave in to open-borders pressure groups.

Making these tough choices now is what most voters want. The candidates of both parties in the next few months will either adjust accordingly or lose elections.