Not me. Or, rather, I think the evidence suggests that mandate is a meaningless concept. America went to the polls in 2000 and whatever you think of what went down in Florida, clearly more people overall voted for Al Gore than for George W. Bush. What’s more, a substantial minority of people voted for a candidate who thought Gore was insufficiently leftwing. And the exit polling made it clear that Bush had the edge over Gore on a bunch of “character” issues. This series of facts, combined with the regnant ideology of mandate-ism, led a lot of pundits to conclude that Bush would, due to his lack of mandate, curtail his agenda. In fact, he did no such thing. And while that was bad for the country, the lack of a mandate wasn’t a practical problem.
That’s not to say that a president can just do whatever he wants. But Congress is an autonomous actor in this. Things that there’s only weak congressional opposition to (tax cuts) are easy for a committed President to implement, and things that there’s strong congressional opposition to (Social Security privatization) are hard for a committed President to implement. As it happens, Ted Kennedy and George Miller were open to doing something NCLBesque during Bush’s first term and so it got done. But had those guys had safe seats, they weren’t coerced by fear of Bush’s popularity into working with him, and had they disagreed on the merits with the testing-and-accountability idea it just wouldn’t have happened no matter how much of a “mandate” Bush acquired.