This is perhaps the most important and least understood fact in today’s Washington: Presidents polarize. As the effective leader of one of two political parties, the president is inevitably a polarizing figure. And Obama himself is a special case. Last year, a Gallup poll found a difference of 76 percentage points in how Republicans and Democrats assessed his administration. That tied the gap measured in the fourth year of George W. Bush’s term as the most polarizing on record…

“Whatever people think about raw policy issues, they’re aware that presidential successes will help the president’s party and hurt the opposing party,” Lee told me. “It’s not to say they’re entirely cynical, but the fact that success is useful to the president’s party is going to have an effect on how members respond.”…

But today’s intense polarization means that most any bill associated with Obama is automatically targeted for defeat by Republicans. Policy compromise, as the White House has found out again and again, isn’t enough to overcome the zero-sum world of modern politics. So in Obama’s second term, in which Democrats have no real shot of recapturing control of Congress, the single biggest impediment to Obama’s legislative agenda might be … Obama — or at least the Republican reaction to Obama.