Apparently you aren't aware that it is the Supreme Court which determines what is constitutional and what is not, not Congress.
I do not think that is entirely accurate. How can the other two branches properly discharge their oaths to "defend and protect" the Constitution if they are not allowed to determine what is constitutional and what isn't? And when the courts exceed their authority in their rulings (Dred Scott, Roe, Doe, Lawrence v. Texas, etc.), are the other two branches to just stand by and allow such perversions of the law? No, they cannot since they have taken oaths to "defend and protect" the Constitution. Clearly, the courts are not the ONLY arbiters of what is constitutional and what isn't. Who is to hold bad judges accountable? Why is there a remedy of impeachment of bad judges?