An eager reader reminds me to finish my breakfast with a helping of crow.

Back in April, Gordon Howie suggested that Larry Pressler was positioning himself to run for Tim Johnson's Senate seat. I deemed the assertion nuts; Howie was simply putting 2 and 2 together and getting 47.2 again. Howie was gluing Pressler's argument for gay marriage onto Howie's own threadbare assertion that the Republican Party is a bunch of liberals.

But comes now candidate Larry Pressler, making Howie half-right with his official announcement that he will run for Senate... as an Independent.

Empirical evidence says Pressler is the longest shot in the race. South Dakotans have elected one third-party Senator, James. H. Kyle, who won as an Independent in 1890 and as a Populist in 1896. That means we've picked just 1 out of 23 elected Senators from something other than the GOP and Dem pools in 43 Senate elections. That puts Pressler's historical Indy odds between 4.3% and 2.3%.

So with Larry in, who runs how?

Pressler, of course, bids for every vote he can get, from every party. He plays to the vast unideological middle. He teases Democrats, hoping to peel away some Indian and moderate voters.

But Pressler focuses on the spicy Republican enchilada. If Mike Rounds wins the GOP nomination, he plays to the Republicans who think Rounds is a rich, lucky, but talentless power-grabber with no real vision for governing. He tells his old Republican friends that this is their chance to shut the Rounds machine down but, with Pressler promising to serve only one term, to clear the decks for a 2020 run by some shinier young light of the party. If Stace Nelson wins the GOP nomination, Pressler points to Nelson's Tea Party/Ted Cruz-ity as exactly the kind of theo-Birchy radicalism that drive him away from the Republican Party and offers his mainstream Republican friends a lifeline. If Rhoden wins the nomination, we giggle about having two Larries on the ballot, and Pressler runs on record, experience, and better French skills.

The Republican nominee fights the battle mostly on GOP and Indy grounds. The Republicans know they have nothing to offer Dems, so they just try to prevent defections, keep their base fired up, and spend all the money they can to ceaslessly ridicule Pressler.

Rick Weiland still travels the state and shakes every hand in every town. He amplifies the attacks Pressler uses against the GOP nominee (Rounds the rich schemer, Nelson the ideological nightmare...). Weiland's goal outside his party ranks is to peel votes away from the bigger, richer, front-runner GOP. Republicans make up 46% of the current electorate; get just five percentage points of that group to vote Dem, induce a similar slice to vote for Pressler, and the Republicans are down to 36%.

But Job #1 in this three-way for Weiland is party unity. Assuming Pressler can run a credible campaign, Weiland watches with glee as Pressler and the GOP nominee divide both the GOP and the Indy vote. Weiland reminds every Democrat that Republicans have nothing to offer them. Democrats currently make up 35% of the electorate. Get them all to come vote Dem, add those GOP defectors mentioned above, draw some Indies, Weiland cracks 40%, and Weiland-Rounds/Nelson-Pressler becomes Clinton-Bush-Perot.

Pre-Pressler, Weiland's chances of winning in November depended significantly on whether Nelson could derail the Rounds money train in the primary. But with a credible Pressler putting a third line on the November ballot, Weiland's prospects against Rounds just picked up. A credible Pressler forces Rounds to divide his campaign resources. Plus, there is a certain anti-Rounds contingent that might mark Mike's name in a two-man race, or leave that line blank, but will never vote for a Democrat. Pressler gives those anti-Rounds voters a way to let off their steam in November and increases the chances that Weiland can win.