For one thing, the jobs have starkly contrasting personalities.

While political executives and legislators can both be worthy politicians, one is charged with executing, the other with maneuvering, compromising, committeeing, a bill in the hand is worth two in the bush.

Voting “Present” is not a realistic option for executives. Even at his lowest approval ebb yet (42%), Obama is still much better approved as president than his recent colleagues of either party in Congress.

For legislators, there’s always another day, another session, another amendment, a committee study to authorize. Obama’s roughly five-dozen healthcare town halls last year could easily be seen as a hearing.

Besides Obama’s deference to a Democratic Congress in such matters as writing the $787 billion economic stimulus bill as his first major presidential legislative signing, he also seems to favor commissions — to study the deficit solution, the oil spill cause. Legislators can notoriously be for something before they are against it; executives either sign it or not.