The same one that was ignored about 4 years ago, yes, that one.
You believe the senate is constitutionally compelled to give advice on supreme court nominations? Does every senator have to give it, or is it okay if only a few do so? Did none of the Democrat senators give any advice? Did the Republican "Wait until after the election" not count as advice? As far as I know, many words were shared between the interested parties - surely some of them could have been legally interpreted as "advice"?
Edit reply due to rate limit:
> Same situation, different outcomes, and funny how both satisfy the demands of the Constitution.
Well yes. If the constitution requires the senate's consent on candidates, then obviously both giving and withholding consent is allowed - what you call "Same situation, different outcomes".
Of course the Republicans where hypocritical in their justification of their actions, but I fail to see how the constitution was broken.
So 4 years ago they "weren't constitutionally compelled to give advice", whereas now they're following the Constitution's "clear direction on the structure of government"? Same situation, different outcomes, and funny how both satisfy the demands of the Constitution. I guess it must be one of those documents where you can do whatever you want and say it's what the Constitution says.