Good article. I'm thinking the Supreme Court will probably uphold. Hard to argue for taking DNA from a suspect if its irrelevant to the charge (The original assault charge I mean). A line has to be drawn somewhere about which evidence and when it can be taken from someone.
Say you drink form a bottle or smoke a cigarette and throw it away and they take it from the garbage and match it up. You don't need a warrant to pick through trash or pick up butts. Its been done this way for a while now too.
It depends on how the DNA is retrieved. FWIW DNA is an awesome tool in identifying criminals. I keep distilled water packets,DNA swabs,ect in my car at all times. Every single burglary,recovered car theft or any felony type crime I attempt to gather DNA. It works and it works quite well. It has helped us clear a number of crimes. The nice thing about criminals is that many have been busted before. There are a LOT of people's DNA entered in COTUS.