Democrats have spent the last three-plus years watching as the Republican party tore itself apart -- caught between its emboldened tea party wing and an establishment trying to hold on to power. But, Democrats have real and potentially lasting internal problems of their own, problems that will emerge far more clearly as President Obama's second term draws to a close.

The symbols of the Democratic (donkey) and Republican (elephant) parties are seen on display in Washington, DC on August 25, 2008. The Democratic National Convention kicks off Monday in Denver Colorado followed by the Republican National Convention next week in St. Paul, Minnesota. AFP PHOTO/Karen BLEIER (Photo credit should read KAREN BLEIER/AFP/Getty Images)

Andy Kohut of the Pew Research Center wrote an important piece detailing the coming fight within the Democratic party over the weekend.  In it, he notes that the split between liberal Democrats and moderate/conservative Democrats is not simply ideological but also demographic.  Kohut points out that women, whites and highly educated affluent voters make up the lion's share of self identified liberals while moderate and conservative Democrats tend to be male, less well educated and poorer.

Then there's this from Kohut:

While Democrats share many core values, there are a number of ways that liberals differ sharply from the rest of the party and the rest of the country.

First, in-depth Pew Research surveys find that many liberals are cynical about achievement. Most don’t agree with the statement that “people can get ahead if they work hard,” and relatively few fully agree that they admire people who have become rich through hard work.

Second, liberals give low priority to dealing with the budget deficit, a major concern for much of the electorate, and they are the only political segment that expresses majority support for paying higher prices for the sake of the environment.

Third, liberals are also significantly to the left of the rest of the Democratic Party on social issues. Unlike other Democrats, few liberals say prayer is an important part of their lives, most strongly favor same-sex marriage, nearly all support abortion rights, and a majority support a path to citizenship for illegal immigrants.

And fourth, on foreign policy, most liberals reject the idea that the best way to ensure peace is through military strength; unlike other Democrats, a majority would find it acceptable if another country became as militarily powerful as the United States.

Those paragraphs are of vital import -- not just for the coming presidential primary fight on the Democratic side, which may never materialize due to Hillary Clinton's strengths in the race, but also for the 2016 general election and, even more broadly, the state of the Democratic party for the next several decades.

So, why haven't we heard more about these divides within the Democratic party? Two words: Barack Obama.  The president, who beat Hillary Clinton by running to her ideological left and who many Republicans insist is the most liberal president ever, has actually governed -- with a few exceptions -- far more like a centrist that most people realize.

We've written extensively about that fact but this chart, which comes from the good people at Voteview shows that Obama has governed more conservatively than either Bill Clinton or Jimmy Carter did.

Obama's approach to his presidency has made some liberal activists quite angry -- those people who wanted single payer health insurance, Gitmo closed immediately and a less friendly relationship between Wall Street and the White House. But, the ire of liberal activists hasn't extended to liberal Democrats writ large; that group, as Kohut notes, remains the most supportive of the President and his agenda.

The very fact that there is a Democrat in the White House -- no matter how Obama chose to govern -- also helps paper over the quite clear differences that have emerged within the Democratic party.  When the president is a member of your party, there's no disputing he's the leader and what he says, largely, goes.  The party out of the White House, on the other hand, has since forever, seen its fight for control played out in public as a series of ambitious pols tear one another apart for the chance to be the next head honcho.

But, as Obama's term nears its end -- and as the 2016 presidential election begins to pick up speed -- the real differences within the Democratic party will start to draw much more attention.   And, even if Clinton is the de facto nominee for president, you can expect the fight between the liberal, populist, activist base of the party and its more pragmatic, moderate, establishment wing play out in Senate and House primaries in 2016 and beyond.

It's already happened once in the early to middle part of last decade when Howard Dean ran as a liberal insurgent in the 2004 presidential race and the likes of Paul Hackett  tried to challenge the party establishment in the 2006 midterms. While the focus of that split was how the party had reacted to the war in Iraq, it surfaced the early stirrings of the populist vs establishment fight that not only still exists within the party but has grown even more stark in the intervening years.

Make no mistake: That fight is coming.