Somehow, after years of tracking poll numbers and seeing what happens on Capitol Hill and on Election Day, I am still surprised by the extent to which polarization pervades our politics. That split, viewed according to one poll as deeper now than at any point in recent history, allows us to predict that Donald Trump will be seen as a success by his base even before he takes the oath of office.

A month after Election Day, there was a Fox News poll that asked people to predict how Trump's not-yet-in-existence presidency would be viewed. A quarter of Republicans said he'd likely be above average. Three-quarters of Democrats said he'd be below average -- all before Trump did a single thing.

Pollsters have asked similar questions for years, and the gap between anticipated outcomes by members of each party have grown wider and wider with each recent new president. Republicans were 11 points more optimistic about George H. W. Bush's legacy than Democrats. For Clinton the gap was 27 points. George W. Bush, 45 points. Barack Obama, 53 points. Trump, 72.

Trump enters office as the least-positively viewed president-elect in recent history. Why? In part because of fervent opposition from Democrats. In the most recent Post-ABC News poll, only 10 percent of Democrats viewed Trump favorably. In our poll taken shortly before Obama's inauguration in 2009, 54 percent of Republicans viewed him in a positive light. The difference between the parties then was 43 points. Now, it's 66 points. In December 2000, even before the results of that deeply contest election were finalized, 27 percent of Democrats viewed George W. Bush positively. The split between the parties was 64 points, lower than what Trump sees now.

The size of the split in approval of presidents is a new trend. Views of presidents are always higher among members of the president's party, but only recently has the divide between members of each party been as wide.

Trump's not doing great right now -- but Obama was at 10 percent approval from Republicans by the end of 2009. That's about where that number stayed for the next seven years.

We can see that partisan split directly. New data from Pew Research indicates that Americans see our politics as more politically divided than in the past by margins not seen since at least 2004.

That perception exists among members of both parties.

Notice that the recent low in perceptions of a divided electorate came in 2009, at the beginning of Obama's first term. At that point, Democrats were particularly upbeat about the divisiveness of American politics. That attitude evaporated fairly quickly, alongside Republican disapproval of the president.

Things get interesting when we consider how attitudes about the president trickle outward. Pew finds, for example, that Republicans are very optimistic about this upcoming year. The last time Republicans were more optimistic than Democrats was in 2008 -- the last time there was a Republican president.

That optimism -- and the pessimism among Democrats -- stems from the election. More than half of those who think 2017 will be better than 2016 cite Trump as the reason. About 7-in-10 of those who think 2017 will be worse also credit Trump.

But the question being asked wasn't about Trump. It was about the year.

Gallup found another halo effect from Trump's win. Economic confidence spiked in the wake of the election, thanks to "surging confidence among Republicans and independents who lean Republican."

Pew's data found a similar shift among both groups. Republicans and Republican-leaning independents both now have a much more positive view of the Republican Party than before the election.

Over the past eight years, we've seen perceptions of objective policy metrics splintered along partisan lines, too. NPR reported this week that only 4 in 10 Republicans replying to a poll question said that the number of people without health insurance had dropped under the Affordable Care Act. More than half of Democrats and independents gave the correct answer. In Nov. 2015, Bloomberg asked people if the unemployment rate had increased or decreased under Obama. Three-quarters of Democrats correctly answered that it had fallen. More than half of Republicans said, incorrectly, that it had increased. It's safe to assume there's a connection between a lack of economic confidence (as measured by Gallup before Election Day) and a perception that the economy is doing worse than it actually is (as measured by unemployment).

To some extent, that "how will Trump be viewed" question from Fox News may be self-fulfilling. If the past eight years are a guide, Republicans will view his efforts positively and Democrats will view them negatively. How a president is viewed at the end of his term doesn't much to anyone expect that president. How a president perceives what he's doing while he's in office, though, can have significant repercussions on how he leads.

Trump, it seems, may be able to count on strong support from Republicans for the next four years and may be able to count on the most generous assumptions about the decisions he makes. Partisanship alone may make those predictions of his eventually being viewed as a success come true.