Except the national guard is the closest analog to the well armed militia mentioned in the 2nd amendment. The founders didn't think highly of a federal military, so the 2nd amendment was written to empower the states to organize their own militias that could be called upon when necessary. These effectively went away with the founding of the national guard since the Federal government ultimately also has control over the national guard and the 2nd amendment was interpreted to give the states freedom to regulate guns. This was the understanding until starting 2008.