Even by the standards of the highly charged immigration issue, what’s been happening among Republicans in recent days is, well, shocking.

First came Herman Cain, now a leading contender for the party’s presidential nomination, arguing for an electric fence at the border that would be powerful enough to kill people.

Next, the other leading contenders, Mitt Romney and Rick Perry, devoted a large portion of Tuesday night’s Republican debate to a so’s-your-mama argument, complete with physical contact, about who was softer on illegal immigrants.

Then, Wednesday morning, senators brought Janet Napolitano to testify on Capitol Hill, and Republicans on the Senate Judiciary Committee put the homeland security secretary through a hazing ritual that stopped just short of making her climb an electrified fence.

Chuck Grassley, the ranking Republican on the committee, accused immigration officials of “deceptive marketing practices,” and he suggested that the administration is secretly seeking amnesty for illegal immigrants.

Sen. Orrin Hatch of Utah quizzed Napolitano about allegations that the Immigration and Customs Enforcement agency thinks that apprehended illegal immigrants “deserve their own barbershop.”

And Sen. Jeff Sessions of Alabama said immigration authorities had “no confidence” in her leadership and suspected her agenda was really “large-scale amnesty legislation.” When Napolitano tried to answer the harangue, Sessions began to shout at her. “You should be paying real attention to them, not rolling your eyes at them,” he lectured.

“I’m not rolling my eyes,” the witness replied — although by the end of Sessions’ diatribe, her eyes were glistening.

After two hours, the jolts ended. “You want to add anything else?” the chairman, Vermont Democrat Patrick Leahy, offered.

“I’ve enjoyed being the witness here today,” Napolitano answered.

Spectators laughed at this claim, which, had it been made in earnest, might have violated the law against lying to Congress.

PROBLEMS GO WAY BACK

As Napolitano reminded the lawmakers more than once, many of the things they were most upset about were based on policies that predated the Obama administration. But that’s what the immigration fight is all about. Multiple congresses and two administrations have been unwilling or unable to hammer out an overall solution to the problem. The only thing that changes is conservatives’ ever-angrier rhetoric — even though it antagonizes the nation’s fastest-growing voting bloc.

Cain may be the most incendiary with his endorsement of electrocution, which he has alternately defended and retracted. But at the debate in Nevada, the candidates were red-faced as they traded soft-on-the-border jabs.

“You hired illegals in your home and you knew about it for a year,” Perry said to Romney, accusing his rival of “the height of hypocrisy.”

“Almost half the jobs created in Texas were created for illegal aliens, illegal immigrants,” Romney said to Perry.

“You,” Perry accused, “were for amnesty.”

“If there’s someone who has a record as governor with regards to illegal immigration that doesn’t stand up to muster, it’s you, not me,” Romney accused.

The quarrel drew in the me-too candidates such as Michele Bachmann, who falsely claimed that President Obama’s “uncle and his aunt … are illegal aliens.”

After Tuesday night’s performance, Napolitano must have known what to expect Wednesday morning as she took her seat.

Democrats tried to puff her up (“tremendous job protecting America … heck of a lot of progress,” Leahy congratulated her), and they attempted to direct the discussion toward less incendiary topics.

Ranking Republican Grassley, however, bored in on immigration enforcement, directing a series of insults at the administration: “far from transparent … less than forthcoming … alarming … deceptive statistics … blatant attempt to circumvent Congress.”

REDUCED TO SHOUTING

Napolitano clenched her jaw as he spoke. In her deep, gruff voice, she replied curtly to Grassley. Was she going to allow illegal immigrants to work? “Well, that happens now, senator.” Would she reject a memo calling for amnesty? “I’m not going to speculate on a memo I haven’t seen,” she said.

Sessions, though, felt free to speculate that Napolitano spends “more time talking with the activist groups” than with immigration officers, contributing to low morale and making it “more difficult for them to act effectively to apprehend people here illegally.”

Napolitano gave Sessions a skeptical glance. “You’re very disdainful about that?” he said, then shouted: “These are people on the front lines! You’ve not been out there!”

On the contrary, senator. The front lines in the immigration fight are often far from the border. 

Dana Milbank’s email address is:

danamilbank@washpost.com