When you’ve got a book to plug or a movie to shill, you go on the Tonight Show. Also, it appears, if you’ve got legislation to move, and economic plan to sell, and an electorate that needs a pep talk. Thus Barack Obama will take the unusual step of going on with Jay Leno as a sitting President Thursday night. Considering the communications challenges the Administration faces, it makes sense that they would expand the venues for getting their message out, and Leno, while he doesn’t draw the audience a prime-time speech would, does still represent a gateway to the broad American middle any President wants to reach. It’ll be an interesting challenge in terms of setting the tone—for both the host and the guest.