The failure of Congress and two presidents to enact immigration reform is plunging the nation into an ugly future. Call it the Arizonification of America.

Quite apart from the ghastly shooting of Rep. Gabrielle Giffords (D) and 19 others in Tucson, Ariz., the state truly has become, as Pima County Sheriff Clarence Dupnik described it, “a mecca for racism and bigotry” — largely over immigration.

It has become a state of Minuteman vigilantism, death threats against politicians and judges, talk-radio demagoguery, and bullying of Latinos and rival politicians by “America’s toughest sheriff,” Joe Arpaio of Maricopa County.

Now, governors and legislators in 23 other states are considering following Arizona’s lead in directing local police to act as immigration officers. And politicians in several states are contriving to, in effect, amend the U.S. Constitution to deny citizenship to children born in the U.S. if their parents are illegal immigrants.

All this represents a high-water mark in the influence of the “nativist lobby” — a richly funded assemblage of national and local groups organized by Michigan ophthalmologist John Tanton.

The groups, which have gained respectability, include the Federation for American Immigration Reform, the Center for Immigration Studies and NumbersUSA. But some investigations have tied Tanton to white-supremacist ideology as well.

The move to end birthright citizenship is led by Kansas Secretary of State Kris Kobach, who is affiliated with FAIR’s legal arm.

Tanton’s groups are making use of economic hard times to argue that immigrants — legal and illegal — are stealing jobs from Americans and straining government budgets. It’s largely bogus because immigrants tend to take jobs that Americans won’t or can’t do and because illegal workers pay taxes but can’t get benefits.

If Congress had acted on immigration reform under President George W. Bush — it failed by five votes in 2007 — or if President Barack Obama had pushed it in his first year in office, as he promised, it might have included “impact aid” for communities with large undocumented populations.

In the present climate, attacks on illegal immigrants by radio talk-show hosts, politicians, vigilantes — and Arizona’s Senate Bill 1070 — invite profiling of Latinos in general, giving the trend a racist tinge.

As immigration reform  advocate Rick Swartz told me: “There’s a long history in our country of demonizing ‘the other’ — Catholics by the Know-Nothings, Chinese, blacks, Jews. Americans ought to fear we’re in another one of those periods now.”

Polls show that 60 percent of Americans support Arizona’s police enforcement law but that just as many support giving illegal immigrants a path to citizenship.

But GOP victories in 2010 will make it impossible for Congress to address the immigration problem constructively.

The prospect is for harsh enforcement measures to be considered in the House, then get blocked in the Senate or vetoed by Obama, producing continued federal stalemate — and state activism.

House immigration policy will be overseen by two longtime restrictionists, Judiciary Chairman Lamar Smith (R-Texas) and immigration subcommittee Chairman Elton Gallegly (R-Calif.)

Smith has indicated he wants to enact mandatory electronic verification of the citizenship of all new employees — a step that might lead to mass firing of undocumented workers. Some pro-immigrant reformers say they could support “mandatory e-verify” if it were accompanied by steps to enable presently undocumented workers to gain legal status. 

But Republicans — and increasingly, even moderates — are opposed to anything smacking of “amnesty,” either because they fear the wrath of nativists or because of the prospect that former illegal immigrants will vote Democratic.

Interestingly, one of the harshest of all anti-immigrant Republicans, Rep. Steve King (Iowa), was expected to chair the immigration subcommittee, but he was displaced by Gallegly. King blamed Speaker John Boehner (R-Ohio), who King said is “not very aggressive on immigration.”

If that’s so, there will still be intense pressure for restrictive action, including a Congressional ban on birthright citizenship from FAIR and allied groups.

In the nation’s capital and around the country, however, political leaders should be worried that conditions in Arizona will spread nationwide.

A brief recent history of events in the state prepared by the National Day Laborer Organizing Network includes neo-Nazi harassment of worker sites, lawsuits charging racial profiling, gun violence and verbal war between Arpaio and Phoenix Mayor Phil Gordon over raids through Latino neighborhoods.

In October 2008, Arpaio sent a 60-member SWAT team on a 2 a.m. raid of the Mesa, Ariz., city hall and public library, hunting illegal immigrant janitorial employees.

In May 2010, Gordon announced he had received 5,000 threats — some of violence and death — for opposing S.B. 1070.

When federal Judge Susan Bolton halted enforcement of major parts of the law, she received hate mail and death threats.

And so did Judge John Roll, when he ruled in 2009 that illegal immigrants could sue a local rancher on charges of harassment. Roll died in the Tucson shooting rampage at the hands of deranged gunman Jared Loughner.

Loughner had nothing to do with the immigration issue, but there has been plenty of other ugliness in Arizona over it. Does America really want that to metastasize nationwide?