First, New York state is not simply handing tax returns over to congress willy nilly... The chairmen, (only of 3 specific committees by law), that requests under federal law, a persons tax returns from the Treasury dept, can request from the state of NY, the same year's tax returns, from the state of Ny, IF THE SAID PERSON's residence is in New York, and he files his taxes there.
They do have to be requested by these 3 chairmen to get them AFTER they have filed a treasury dept request....
Regardless, I don't think this is such a good idea... and it is likely that Nadler, or the other 2 chairmen allowed, do either. It is better for them to keep this as a federal fight, between congressional power and the executive branch, and allow the third branch of gvt, give a decision based on the US Constitution.
It is more than likely, the Congress will win, the executive branch will lose... the law says ''shall''...
Our founders made Congress as who was in Article 1 of the constitution, the executive branch as Article 2.... Congress in their minds, is more important in a democratic republic, than the executive, because congress represents, we the people...
Also, the purpose of needing the tax returns and his financials is because he is likely breaking the emolument clause of the constitution... among other reasons,
all legitimate congressional duties... President Trump will lose this battle with ease and the supreme court will likely not even take the case, it is so clearly within congress's power and in the Law.