a) If push comes to shove, Federal Law trumps State Law. That principle was established in 1865, more or less. and,
b) It's not like the Feds actually have to ASK. The beauty of this kind of Federal program is that it doesn't require a presence in the States. It would be a WEBSITE and some letters arriving in your mailbox. There wouldn't be like the Federal civil rights laws, with dramatic black and white news footage of Federal Army troops escorting a health insurance plan down the sidewalk to the Alabama Legislature, being spat on all the way, only to find Governor Bentley blocking the door.
And while we're on the subject, can the Democratic party PLEASE stop appeasing this silly 'states rights' issue by handing States federal money to administer federal programs? This is not only irresponsible, but politically stupid. If the Federal government pays for a program, the Federal government should administer it! No more of this nonsense about handing Federal dollars to teabag Governors, letting THEM hand it out and take credit for it, and then turning around and shouting nasty names at Washington. Every one of those teachers, cops and fire fighters who was kept afloat by FEDERAL money last year should have gotten a check from the FEDERAL GOVERNMENT, DIRECTLY.