As recently as Jan. 15 — nine days ago — Gallup’s daily tracking poll showed Mitt Romney leading Newt Gingrich by 23 points. In fact, a day earlier, Gallup showed Gingrich running third, a point behind Rick Santorum.

And as of today, Gallup has Gingrich leading Romney by four, 31% to 27%. The pollster published this image this afternoon:

This really is astounding. Romney’s national support has dropped 10 points in nine days — not because of any new scandal or humiliating gaffe, but because his support was fairly tepid and weak, and voters were easily swayed away.

For the record, I still believe Romney is the frontrunner and likely nominee, in large part because of his financial and organizational edge. I also believe Romney has demonstrated an ability to destroy Gingrich once — remember when the former Speaker had a big lead in Iowa, right before Romney spent millions to tear him down — and will likely do so again.

But when a frontrunner sees a 23-point lead evaporate this quickly, the ripples of panic in Republican circles are well justified.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.