Let's say you open the door and the police officer pushes his way in or puts his foot in the door. There's not much you can do that wouldn't get you physically pounced on at that time. So, what I would do is I'd pull my phone out and begin recording and tell him to please back away from your door, that you don't consent to any searches, and you don't consent to him being in your home. If he sticks his foot in the door, he's determined to gain entry into your home. But remember, if he does so illegally like that, and that's illegal. He's not allowed to do that without a search warrant. If he does that illegally, a good lawyer will suppress all of that evidence. Anything that he obtains after that is illegal and not admissible against you.