When Democratic incumbents retire in red states, that often portends difficulty in terms of holding the seat. But this case may be an exception. A recent PPP poll found Johnson losing to Rounds by 11 points, but if ex-Rep. Stephanie Herseth Sandlin ran in his stead, she'd still trail, but by a much small 4-point margin. I suspect the difference boils down to tenure: Johnson has been in Congress since 1986 (starting in the House), while Herseth Sandlin served a little over six years before losing in 2010. Sometimes you're better off running without a lengthy history of votes and public statements attached to your name.
It's no sure thing that Herseth Sandlin will run, though, and if she opts not to, all eyes will turn to U.S. Attorney Brendan Johnson, who is Tim Johnson's son. While Johnson is largely unknown and thus fared poorly in PPP's poll, he may actually have more upside than Herseth Sandlin: As a prosecutor, he has no unpopular votes to defend and can present the sort of law-and-order image that often works well for Democrats running on difficult red terrain.
And it's not necessarily smooth sailing for Rounds, either. Many conservatives view him as a "moderate," a dreaded label in a GOP primary. They'd likely prefer Rep. Kristi Noem, the woman who unseated Herseth Sandlin. Noem is being cagey, with her campaign saying she "hasn't ruled anything in or out," but if she were to run, PPP's survey showed the nomination would be a tossup between her and Rounds. And in various general election matchups, Noem makes the race noticeably more competitive.
But make no mistake about it: Regardless of whom either side puts forward, this is going to be a very difficult hold for Democrats, who face a very difficult Senate landscape overall. The one bit of optimism I might offer is that Dems managed to keep an open Senate seat in North Dakota blue last year, thanks to Heidi Heitkamp's brilliant campaign and the weakness of her opponent. We'd be very lucky indeed to replicate that success, though, but we'll be following all further developments here very closely, as always.