I do think the Obama 2008 vibe shift comparison some have used for this week has some real accuracy for this moment. But I hesitate to use it myself. I refuse to be too confident about such a pivotal moment.
We knew then that McCain was on the wrong track for America and that we couldn't continue Bush II policies, but McCain was not a deranged autocrat with a history of insurrection who'd packed a corrupt Supreme Court. The stakes are much higher today, the situation is far more dangerous and this entire cycle is far more unstable. We can be happy and excited but we can't let our guard down for an instant.
That said... yes, I do think there is a real similarity to '08 at the immediate moment.