Even Madison (as well as other founding fathers) recognized that this practice wasn't kosher according to the constitution
I looked this up. Madison only expressed this view long after he retired, in the so-called "detached memoranda." This was a flip-flop, as he was on record as supporting the chaplaincy while still active in politics. In addition, I could not find another founder who who agreed with him.
The clincher for me is that George Mason never once objected to any Federal public displays or references to religion, which were a commonplace in those days.
Yes, what about it? The NO was written by the last Continental Congress who was still under the authority of the Articles of Confederation and not under the Constitution which had not been approved yet. Moreover, that particular sentence was a last minute addition which was even watered down so the final version didn't mention religious institutions and the active support thereof. BTW, here is more detailed information on the Northwest Ordinance.
What about letting religious services to be held at the Capitol building?
Now I don't know whether religious services at the Capitol building have been explicitly ruled to be constitutional but lets assume that they haven't, the simple fact that they have been held at the Capitol doesn't automatically make this practice constitutional. It may well be that those who introduced this practice (or other practices pertaining to the involvement of the state with religion, whether sectarian or not) didn't think about its constitutionality or simply didn't care. And even if it is unconstitutional it can still go on if it's not challenged in court.
And religion is always a pretty delicate issue which means that challenging something like that in court can cause you a lot of trouble. In other words, even if you have the First Amendment on your side, you're still the party pooper or worse.
I looked this up. Madison only expressed this view long after he retired, in the so-called "detached memoranda." This was a flip-flop, as he was on record as supporting the chaplaincy while still active in politics. In addition, I could not find another founder who who agreed with him.
The clincher for me is that George Mason never once objected to any Federal public displays or references to religion, which were a commonplace in those days.
Well, of course he did. He was after all a politician. Do you really think he was eager to commit political suicide while he was still active? So of course it was easier for him to speak his mind after he retired.
You make it sound as if he changed his mind after he retired but from his writings (e.g. the Detached Memoranda or in a letter to Edward Livingston) it's clear that he did not and that it's more likely that in those instances you mentioned he rather acted against his convictions because he realized, like most politicians, that being pedantic on such issues doesn't take you very far. (on a side note: I always thought Madison was one of those who voted against the institution of congressional chaplains)