The Clinton campaign and Democratic National Committee called for using far-right candidates “as a cudgel to move the more established candidates further to the right.”

It’s important to note that this also applied to Democratic candidates. With the Republicans moving 100 miles to the Right, Democrats didn’t think anyone would notice them moving 20 miles to the Right. Clinton and the DNC are just as responsible for the Overton window shift as the Republicans are. If not more so. Had they embraced and supported people like Sanders, who would have absolutely demolished Trump, we wouldn’t be in this fucking mess.

The Wikipedia entry on that one is a fun read. I’ve heard most of these possible origins before, but nobody is actually sure of the true origin of the phrase. It’s kind of frustrating, but also pretty neat that we still use a phrase long after we forgot where it came from.