While writing about senators' evolving opinions on the matter, I'd be remiss not to point out Obama's erstwhile support of the filibuster. As a senator in 2005—when Democrats were in the minority—he spoke against dismantling the filibuster. "BREAKING," Chris Hayes tweeted. "Everyone's a hypocrite on process."
Does it matter that Mitch McConnell or Harry Reid or Barack Obama changed their position on the filibuster depending on when it was most beneficial to their party? To answer that, I think you have to ask: is the filibuster quantitatively more expansive today compared to 2005? Obama says yes. His 2005 defense of the filibuster, however, is still worth watching:
President Obama in 2013:
"I realize that neither party has been blameless for these tactics. They've developed over years, and it seems as if they've continually escalated. But today's pattern of obstruction—it just isn't normal. It's not what our founders envisioned. A deliberate and determined effort to obstruct everything, no matter what the merits, just to refight the result of an election is not normal, and for the sake of future generations, we can't let it become normal."
And Senator Obama in 2005:
"If the right of free and open debate is taken away from the minority party, and the millions of Americans who ask us to be their voice, I fear that the partisan atmosphere in Washington will be poisoned to the point where no one will be able to agree on anything."
That hasn't stopped anyone up to now!