Not content to botch immigration policy all by itself, Congress has handed large parts of the job to others to mishandle. It gave the homeland security czar the czarist powers to overturn any law and ignore any court to seal the border. Now Michael Chertoff is clear-cutting a forest of regulations to wall out Mexico by the end of the year. And through the program known as 287(g), his agency is parceling out duties to a growing number of local police and sheriff’s departments, raising an army of junior deputies in the war on illegal immigrants.

To see how unhinged things have become, it pays to zero in on the squalid doings in Maricopa County, Ariz. It is home to Phoenix, the country’s fifth-largest city, and the largest 287(g) program anywhere.

It is run by the county sheriff, Joe Arpaio, who has built a national reputation for toughness through years of cruelty to prison inmates and an insatiable appetite for publicity. Where most departments have only handfuls of officers trained to enforce federal immigration laws, Sheriff Joe, as he is known, has 160. Their efforts are supplemented by what the sheriff says, without apology, is a 3,000-member “posse.”

For months now, Sheriff Joe has been sending squads of officers through Latino neighborhoods, pulling cars over for broken taillights or turn-signal violations, checking drivers’ and passengers’ papers and arresting illegal immigrants by the dozen.