The President will hold a press conference later today. Many of the questions will not doubt focus on the administration’s response to the disaster in the Gulf of Mexico. That response has been fitful, uncoordinated, and unsuccessful, so the President deserves to be grilled on what he will be doing differently going forward.

But, the press conference also demands something more. President Obama must do well what candidate Obama brilliantly. He must create a narrative that explains to average folks the many discrete tasks his administration has undertaken, relates them one to another and all of them to a sense of national purpose.

In the campaign, of course, the creation of a narrative was easier because the unifying principle of his policies was “change” a contentless noun. Once elected, it became necessary to put some content into the change, to enact actual policies not prospective ones, to choose among alternatives. In a campaign, the electorate can project onto a candidate their hopes, see what they want to see, but once elected, the President has had to disabuse some people whose goals were not his, especially those from the extreme leftwing within his own party. Moveon.org is not the Tea Party of the Left, but it is close.

The President’s day, of course, recognizes no such unifying narrative. A series of unrelated events and challenges arise and must be dealt with, most of the unexpected. Certainly no one expected the disaster in the Gulf, nor that the North Koreans would sink a South Korean ship, and the two events have nothing to do with one another except that both have diverted attention away from the immigration reform and climate change legislation the President was hoping to pursue. It is easy and understandable to fall into reflex mode, but successful presidencies rise above the fray by keeping before the country a consistent and coherent narrative that encompasses new challenges but keeps the political focus on the goals the candidate set before the country at election time.

President Obama would be well served by using today’s press conference to speak about his vision of the common good. It is an amorphous phrase, of course, but it would allow him to describe his policies and distinguish them from the Republicans, in useful ways. The financial reform measure before Congress is an effort to protect the investments of average folk from the shenanigans of a few investment bankers on Wall Street. The health care reform was primarily an effort to ensure that the health care system includes all and lowers costs for average folks rather than a system built to line the pockets of the insurance companies. And, whatever measures he announces regarding offshore oil drilling must be seen as an effort to protect the ecosystem we all share from an irresponsible corporation and a corrupt government oversight agency. These different policies are discrete, but what unites them has to be the ideological sensibility the President brings to resolving them. This was a gift FDR and Ronald Reagan both had, to be able to explain their various proposals by referencing them back to their electoral themes.

One press conference does not make or break a presidency. That said, President Jimmy Carter’s “malaise speech” (which never mentioned the word malaise) came to encapsulate the difficulties and the depressiveness of his administration, and he never recovered from it. If a President does not provide the theme, the press will, and it will be less flattering. Obama’s style lacks the folksy charm of Reagan, or the patrician charm of FDR, but he can be enormously effective. In these last few months before the midterms, and with much of his legislative agenda hanging in the balance, President Obama needs to get out in front of his own challenges and provide the rest of us a narrative that explains how he is approaching those challenges, and how we can better understand his proposals. By uniting his policies and his politics to his perception of the common good, the President gives us a hermeneutic with which to understand and judge him. That is better for him and for us than letting the events of the day provide a chaotic and incoherent narrative, driven by events not by men. The President should announce his plans for off-shore drilling, of course, but most importantly, he must articulate, today and always, his vision of the common good and how his policies relate to it.

Michael Sean Winters