Now that Mayor Bloomberg has sent investigators into Arizona to report on what he insists is lax enforcement of federal regulations at guns shows, the question that leaps out is what retaliatory investigation Arizona is going to launch in New York. The first thing that comes to mind is whether Governor Brewer, who is rising to fame for her use of state law to deal with undocumented aliens, is going to send Arizona officers into New York City to see whether the Bloomberg administration has been looking the other way in respect of undocumented aliens working in New York City.

Just for the record, The New York Sun doesn’t have any evidence that Mrs. Brewer is plotting to launch such an investigation. If she were, we’d be against it. But it wouldn’t be any more outrageous than the mayor of New York City sending investigators into Arizona to look into lax enforcement of federal regulations in respect of guns. One could argue that Mr. Bloomberg’s demarche is even more outrageous, because the impact in New York of gun sales in Arizona is minimal. But the impact of New York’s lax enforcement of the immigration laws has a huge impact on interstate commerce.

Moreover, the federal government has a clear right and power to establish a uniform rule of naturalization. It’s right in the Constitution. We happen to be against using that right to restrict immigration, but at least the federal government has constitutional authority. So if Mrs. Brewer were to catch New York City thumbing its nose at federal regulations, it might catch Mr. Bloomberg in a legal pickle. Gun control is different. The federal government has no power — indeed, is explicitly denied the power — to infringe upon the right of the people to keep and bear arms, in Arizona or New York. That’s also in the Constitution. So if the Bloomberg raids in Arizona get challenged in court, why it’s just possible the mayor will be made a fool of.

Certainly the Columbia District lost its case in spectacular fashion when it tried to block Dick Heller from keeping an assembled pistol in his home, and Chicago lost when it tried to regulate guns. The Supreme Court didn’t absolutely outlaw local regulation of guns; local authorities can bar them in schools, it said at one point by way of example of what it might countenance, though the federal government has been blocked from trying to regulate the carrying of guns in schools. The question that is raised by the Bloomberg raids is whether a state or city official has the authority to regulate the sale of guns in another state. Now that the mayor has asserted that he does, we wouldn’t be surprised were Mrs. Brewer — or another governor — to send undercover officers into Mr. Bloomberg’s home town to see how far the principle of out of state raids extends.