Maybe I’m mellowing with age but this strikes me as less unreal now than it did a few months ago. A question for the lawyers in the audience: There’s nothing unusual about foreign nations chipping in with amicus briefs on U.S. legal matters, is there? In two minutes of googling, I found this Supreme Court amicus submitted by the European Union in a death penalty case arguing that international consensus opposes executing criminals under 18. Their stake in that matter is surely less than Mexico’s et al. in how Arizona treats its citizens who are here illegally, no?

What’s really unreal is that the governments who submitted briefs thought it was a good idea to do so. Whatever marginal legal benefit an amicus filing will bring is surely outweighed by the hugely damaging PR from the perception that they’re meddling in U.S. immigration matters, no? And given how expertly Brewer’s been using this issue for political gain over the past eight months, it was a no-brainer that she’d end up rubbing their faces in it.

The move comes in response to a 9th Circuit Court of Appeals ruling issued Monday, allowing nearly a dozen Latin American countries — Mexico, Argentina, Bolivia, Brazil, Costa Rica, Ecuador, El Salvador, Nicaragua, Paraguay, Peru and Chile — to submit friend-of-the-court briefs in Justice’s challenge to SB 1070, which Brewer signed into law in April and is considered one of the nation’s toughest immigration-enforcement measures.

“As do many citizens, I find it incredibly offensive that these foreign governments are using our court system to meddle in a domestic legal dispute and to oppose the rule of law,” the Republican governor said in a statement shortly after the state’s motion was filed Tuesday evening.

“What’s even more offensive is that this effort has been supported by the U.S. Department of Justice. American sovereignty begins in the U.S. Constitution and at the border,” she added. “I am confident the 9th Circuit will do the right thing and recognize foreign interference in U.S. legal proceedings and allow the State of Arizona to respond to their brief.”

Politico notes that this argument should resonate with conservatives, who worry about U.S. courts applying foreign law to decide cases. Normally that’d be true, but not this time: If the feds want to start following the Mexican government’s lead on how to enforce immigration law, most righties will find that an intriguing possibility.

Latest Rasmussen poll, by the way: Brewer 55, Goddard 39. After this, figure she hits 60 next week?