Priebus and every other leading Republican strategist knows that recent GOP nominees have been weakened by a primary debate stage dominated by fringe characters—along with front-runners doing too little to distinguish themselves from the extremes. The resulting spectacle presents a horrible image of the party to general-election voters, weighing down the eventual winner.

Priebus’ recent declaration that candidates will have to perform above a certain threshold in polls to warrant inclusion in debates, a threshold that will get stiffer later in the campaign, suggests he is aware that he needs to get as many fringe characters off the stage as possible. But he can’t be confident that the poll respondents will oblige and elevate only mature candidates above the bar.

However, if Republican insiders have the wherewithal to contain the support and attention given to their circus acts, then that could greatly aid Priebus’ project. The twin falls of Romney and Palin last week are solid evidence that the party wants to shape up and jettison any distractions. That’s a warning for Democrats to stop laughing at the prospect of another GOP clown show a la 2012 and start preparing to grapple with a more serious opposition.