Pure smokescreen tactics.
I think it has significantly more of a chance of failing than passing. 2/3s of a House and Senate - both - is quite a number to reach. Especially on something so controversial. Even a great many Republicans cringe at the thought of amending the Constitution and taking something out of the hands of individual states and placing it in to the realm of federal policy.
Then, the 38 states required to ratify it for passage is a hefty number as well. States really aren't inclined to hand matters of their own jurisdiction off to the federal government.

That being said, I think this whole mess, though less than likely to end up in ratification and amending, will most certainly result in some deep divisions being drawn through American society. This will become an impassioned debate that fires up emotions on both sites and will result in a whole lot of Americans hating a whole lot of other Americans.

That's the true tragedy here.