When news broke last week that the Democratic Senatorial Campaign Committee (DSCC) had no plans to air more ads in the Kentucky Senate race, it was frequently viewed — including by me — as a sign that the party was conceding the race to incumbent Mitch McConnell. But on Wednesday afternoon Politico's Manu Raju reported that the committee is jumping back in, with a new $650,000 ad buy for Alison Lundergan Grimes.

A source told Raju that the DSCC was encouraged by public and private polling showing that independent voters were moving toward Grimes. Perhaps Democrats are truly seeing this in their internal numbers, and perhaps if you squint at the public polling in a certain way you can come to that conclusion:

But it's also plausible that the party's taking a risk on Kentucky because Democratic prospects have deteriorated in so many other key races. The party's candidates in Alaska, Arkansas, Louisiana, Iowa, and Colorado have all looked increasingly beleaguered. Meanwhile, Pat Roberts has regained ground in Kansas, South Dakota remains a mystery, and Michelle Nunn has gained in Georgia but would likely face difficulty in a runoff.

So throwing some cash back into Kentucky might be a long-shot play for the disadvantaged Democrats, resembling the late moves into Pennsylvania by both John McCain and Mitt Romney during their losing presidential bids. To find out which is the case, it's best to keep an eye on the new public polling.