Modern debates about Presidential Power are often marked by partisanship and the claim that one party is uniquely guilty of violating the separation of powers. I think the better way to think about it is to adopt a neutral principle about what the scope of executive power is, and then apply that consistently. Obviously, one neutral principle is the Founders Constitution - to adopt a perspective and the conception of executive power, and Legislative Power, and Judicial Power that the founders adopted in the Constitution, and then use that to rigorously evaluate what's going on in the modern era. Constitutional discussions are never going to be totally divorced from partisanship, but if you have a fixed standard by which you can decide whether or not the President has violated his constitutional duties, or usurped powers, it becomes a little bit easier to have a meaningful and coherent conversation about whether the President has overstepped his authority. The Constitution grants the President various powers, and there's a meaning and understanding attached to them. It's historically grounded, and if we use that as a frame of reference then we can say whether President A or President B is violating the Constitution, and not have it degenerate into a partisan exercise where one party is claiming that the President has done nothing wrong, and the other party is claiming the President has done something terribly wrong. You could obviously use a different measuring stick for whether the President has acted unconstitutionally, but the original Constitution is a pretty good measuring stick. We all, at some level, venerate the Constitution, and I think that's a better measuring stick than say looking at practice or other possible means of deciding whether the President has gone too far. Practice is notoriously difficult to understand and sift through. It could decide which practices are relevant. How many have occurred? Are they really the same or are they different from each other? That, I think, generates a lot of uncertainty, and lets partisanship creep back in.