Mitch McConnell has a theory of why there are so many cloture petitions these days. It’s not that Republicans reacted to the 2008 elections by declaring a 60-vote Senate and demanding cloture votes on every item that reached the floor, something that had never been the case in the body’s history. No, it’s that Majority Leader Harry Reid (D-Nev.) has been using obscure procedures to deny Republicans the right to offer amendments, leaving them no option other than to avail themselves of the right to filibuster.

If only there were some way to test that theory . . .

Wait, there is!

After all, there are no amendments on confirmation votes. So if a lack of amendments was the main reason for the increase in cloture, then these votes should have been unaffected.

Yet, of course, filibusters of confirmation votes spiked up in 2009 — particularly on executive-branch nominations but on judicial nominations, too.

Basically, before Barack Obama was elected, filibusters against executive-branch nominees were rare; now, they extend to pretty much every nominee.

Yes, Democrats did mount a few filibusters against people President George W. Bush nominated, most notably John Bolton (for U.N ambassador), just as Republicans had filibustered a handful of ambassadorial and other nominations when Bill Clinton was president. But recall that John Ashcroft was confirmed for attorney general on a vote of 58 to 42. With those 42 votes, Democrats could have blocked Ashcroft with a filibuster but chose not to.

So: Yes, Republicans do have some legitimate complaints about amendments. But that has nothing to do with their 1993 decision to force cloture votes on all major issues, or the 2009 decision to shatter Senate norms and insist on a full 60-vote Senate.

It happened with legislation and with nominations. It’s no way to run the Senate. And it can’t — and won’t — last.  Protection for minorities in the Senate makes sense, but requiring 60 votes on everything just doesn’t.