Theodore Roosevelt's 1907 rewrite of the militia laws (National Guard Act) has some constitutional problems, and this is one of them. The Constitution says the States have the choosing of officers for the Militia.
Congress can prescribe the training and equipment of the Militia -- but the Constitution does not give the Congress power to control the training and equipping of the Militia, only "prescribe" equipment and training regimen.
There are other problems as well, having to do with the Congress's pretended power to authorize the President to deploy and use the Militia overseas, for example. Hamilton and Madison would have a big, fat problem with what Bush and Obama have done, sending Guard units to Europe and the Middle East while their home States of Arizona and Texas are being invaded from Mexico.
Right. My point is that the National Guard is not the militia. They are a reserve component of the US Army. Most states do not really have an official, organized state militia.
By law, the NG are members of the Federal militia, which the feds allow the states to use when the feds don't need them.