I'm tempted to agree with you ignoring some concerns mentioned downthread: in wartime (which looks like it is approaching fast), the judicial branch tends to let the executive do what it wishes. Imprison every American citizen with a certain proportion of Japanese blood, for example. And we could quote President Jackson, the president Trump compares himself to most, when he said, "John Marshall [supreme court chief justice] has made his decision; now let him enforce it!" after the court ruled against one of his orders (specifically the order that caused the Trail of Tears IIRC)
But the larger concern is that if you investigate or follow someone around long enough, you'll find a reason to lock them up. And if not, evidence can be easily fabricated (this very ruling facilitates fabricating evidence more effectively!). The courts can do nothing if a prosecutor provides legally (or "legally") obtained evidence of one of the thousands of federal felonies. Would they even if they could? The courts have been obedient servants of the law enforcement/national security apparatus for quite some time now. Plus there are many, many avenues available to Law Enforcement (especially federal) that no longer require any input from the judicial branch, like administrative subpoenas, national security letters. Asset forfeiture requires some but minimal judicial oversight.