President Obama's polarization is commanding much of the conversation this week in domestic politics. The Pew Research Center sparked the issue after issuing a report noting Obama's 61-point partisan gap, the difference between the muscular approval of Democrats and the puny approval of Republicans. In Pew's polling, that's 10 points more partisan than George W. Bush at the same period in his presidency.

The Bush and Obama contrast overstates the point however. Obama is not significantly more partisan than Bush. But Obama is as partisan as Bush and that fact strikes many as new and notable.

Perhaps it shouldn't. I wrote here about three weeks ago that, "the public's approval of Barack Obama breaks along stark partisan lines, mimicking George W. Bush at the same point in his presidency." It was indeed clear within weeks of Obama's presidency that he would not escape the gravity that grounded Clinton and Bush. Obama was, as I wrote here in February, a president roughly as popular as his recent predecessors and less popular than many infant presidencies from an earlier era.

The polarized view of Obama is only newsworthy because transcending partisanship was the theme of his campaign. Obama set a standard for himself that many veteran Democrats, like his secretary of state, were skeptical of last year.

This leaves us with a president who pledged to bridge what he thus far has not. But some perspective is also required.

Obama is not splitting Democrats and Republicans significantly more than Bush. Pew's comparable Bush numbers come from its mid-April 2001 poll, which notably had 36 percent of Democrats approving of W.

We know from Gallup polling, carried out far more often than Pew, that Bush's best standing with Democrats before the September 11 attacks was 37 percent. In other words, the 36-point Pew statistic was at Bush's early peak with the opposing party.

Here is a better, though still imperfect, metric to gauge the political opposition's distaste for Bush and Obama. Gallup averages its data weekly. There have been 11 weekly averages of Obama's approval between January 19 and April 5. When I averaged those together, Obama had a GOP approval of 31 percent. Gallup polled less frequently in Bush's early years. Therefore, I averaged Democrats approval of Bush in Gallup's seven polls from February 1 to April 8, 2001. Bush had a 32.43 average Democratic approval. In short: 1.43 percentage points separate the opposing party's view of Bush and Obama--that's squat in statistics.

If one follows this methodology to calculate Democrats' approval of Obama and Republicans' approval of Bush, there is an even smaller difference (89.5 Democratic approval for Obama compared to 88.9 Republican approval for Bush).

That means, the more accurate partisan gap score is: Obama at 58.5 and Bush at 56.43.  That is a difference without distinction.

That Obama has proven unable to turn America back to less partisan eras certainly resonates with Obama's skeptics. Party divisions are far deeper than rhetoric or personality. They regard issues, lifestyle, demographics and worldview. These divisions have deepened in recent decades due to gerrymandering of Congressional districts, that conservative southerners migrated from the blue to red party and many northeastern moderate Republicans went from red to blue, that partisans are increasingly reading ever-more partisan news and the remarkable pattern in recent decades of Americans more often socializing with likeminded Americans.

Obama's mandate will depend on the middle more than the right flank. But as long as the public and press remember that he once pledged to woo that right flank, his public appeal will always seem not quite what he promised. And as Obama's advisors know, political success is always a game of expectations.