It would seem that anyone holding a strictly Constitutional view would have no objection-- right? Since the army and navy are expressly mentioned in our founding documents, surely the military have a role in protecting us against threats, even domestic?
Contrary to popular opinion, there is no Constitutional proscription against using the military to enforce federal laws. That's precisely how the Posse Comitatus Act, so often misunderstood as an 18th century creation, was passed. Representatives from Southern states, angry that the federal government was enforcing Reconstruction policies by using the military, insisted in 1876 on the Act. The South didn't actually dispute the Constitutionality of troops being used to implement federal law-- the idea was simply to neuter the USG's ability to protect the newly found rights of blacks citizens. In other words, everyone agreed US troops were the proper means to carry out law enforcement, southerners just didn't like the recently passed Amendments to the Constitution and supporting laws, which gave blacks equal rights. Rather than seek an Amendment to the Constitution then, Southerners attacked collaterally, eliminating the means to enforce Reconstruction policies by taking the military out of the equation. Theoretically the USG still had the authority to protect blacks wanting to vote, but no men to carry out that important work.
With this odious history then, I caution fellow liberty lovers from embracing the Posse Comitatus Act as a tenet of freedom. It's history is shameful. It was passed to prevent blacks from not just voting, but from the violent attacks which intimidated them from going to the polls. I can't celebrate any legislation which was inherently racist, hateful, and implicitly conducive to violence.
Why didn't federal agents enforce the laws, you ask?
US Marshals had been around as an arm of the Department of Justice, but they were mostly used to pacify rural, unincorporated federal territories, and to protect the justice system. The Postal Service had some inspectors. And I think the Park Service had some federal officers. But it wasn't until Lincoln created the (creepily named) Secret Service in 1865 that a significant federal police force was borne. The initial mission was to thwart counterfeting. But then an aspiring anarchist (Leon Czolgosz), aspired by a practicing anarchist (Emma Goldman), shot and killed President McKinley in 1901. And since nothing breeds expansion of government more than a security driven crisis, the Treasury Department's Secret Service soon took to protecting the President. But in 1876 the Secret Service was still far too small to help the millions of black Americans who needed protection during election time.
The FBI?
There's no mention of the FBI in the Constitution. The Federal Bureau of Investigation wasn't created until 1935. To give some perspective, the majority of justices presently on the Supreme Court were born before or within a decade of the founding of the FBI. It's not exactly the federal government's most ancient entity, even if it's managed to grab a lot of attention.
So maybe we shouldn't be so quick to object to the notion of the military enforcing federal laws. If the Founders had imagined another means to back up federal laws, don't you think it would have been included in the Constitution?
Grant me this, at least. There are some legitimate reasons the USG might need to set up a checkpoint. Imagine, for example, that a known terrorist posts a YouTube video claiming he's going to blow up New York City using an explosive filled cement mixer on January 1. Wouldn't the federal government, having cause to stop and arrest someone driving a cement mixer and matching that terrorist's description, have the authority to setup checkpoints at certain strategic locations around New York on New Year's Eve? And if so, who to man those checkpoints?
Why not the army? Soldiers have the means, training, and Constitutional authority to protect the country.
How about because Article one allows Congress to raise armies, but fund them for only for two years. That's a pretty clear message against standing, professionalized armies. Not exactly the norm these days-- but the sense it clear. The Founders didn't imagine a massive, all powerful military. Given that, an amateur militia of just drafted youngsters probably isn't who we want investigating possible terrorist attacks.
Who do we want then? Why capable, intelligent, quick thinking, professional investigators, of course. But where to find them?
Well not in the USG. Because nothing in the Article One gives the USG the authority to conduct such operations. The USG does have the authority to repel invasions, protect the borders, and fight wars. Those are great reasons to have and use an army, and use it outside the US, but not to conduct law enforcement operations in the States. But Article One does permit the army to be used to "suppress insurrections," so if the threat is domestic and intended to overthrow the federal government, then the use of the military seems perfectly Constitutional (someone send this to Alex Jones and see how he reacts).
So for this sort of threat then-- an individual seeking to attack inside the US-- those quick thinking investigators we seek should be found at the state level. If New York City is in jeopardy, the Feds need to share that information with Albany, who can work with neighbors in New Jersey, Connecticut, and other states to set up an appropriate response.
I think there's an argument to be made here that if such an attack were against the USG but directed at New York City-- especially if the attacker were a proxy for another country-- then the USG, using the army, would have authority to act. But wherever the USG lacks authority, they shouldn't be enforcing laws and therefore certainly shouldn't be setting up checkpoints. The day I see a federal agent enforcing DUI laws is the day I know it's gone too far-- if it hasn't already.
I dislike the idea of soldiers patrolling around our streets. I'm aware of the no quartering provisions of the Third Amendment and the history of abuses under martial law. I don't want Marines enforcing federal laws, in all but the most exceptional circumstances. But the Posse Comitatus Act is wrong because there's no doubt the 13th, 14th, and 15th Amendments were passed lawfully and are as much the part of the Constitution as any other. Eviscerating these Amendments by removing the authority to use the military to enforce racial equality is not only unconstitutional, it's a shame.
But small government types take heart, this same reasoning would severely limit the size of the USG and existing federal law enforcement. Where in the Constitution is there authority for federal agents to regulate how much water is in a toilet bowl?
Get rid of all of those unconstitutional, wasteful positions. Let the states police that stuff. Let the military protect us from external threats and a few, specific, rare domestic threats. And for God's sake, shutdown the Orwellian sounding Department of Homeland Security.