Only Tangible Policy Positions Will Win Them Elections, The "Center" Doesn't Provide That
We are currently 6 months into the Trump presidency. The Republican Congress has bungled the ACA repeal attempt while Trump has haphazardly played the role of a president. Currently, there is a Muslim ban in effect and waiting for Supreme Court review. A wall on the southern border with Mexico could potentially be funded by Congress. There are a handful of other policy attempts being worked on, but so far no real piece of legislation has been signed by the Trump administration. The GOP has effectively put forward a slate of policy positions that their voters can observe, The Democratic Party needs to do the same for future elections.
Democratic standpoints thus far been of pure and overt rejection. Democratic politicians have gone out on limbs to say things like "this is awful", "we don't support this", "we would never do this". The Democratic Party has positioned themselves as a party of opposition, as a party of "we are not the other guys". It is similar to the Clinton campaign's message of "look, we aren't the other guy,vote for us". This strategy will not bode well come the 2018 midterm elections nor the 2020 presidential elections. Democrats need to put forward actual policy positions if they want to win elections.
Being a party of opposition is the same thing as being a centrist political party. Democrats are only considered on the "left" because they aren't the same as the Republican party, or the "right". That isn't how a political spectrum should work.
Analyzing the election debate surrounding Trump's "wall" is a good analogy to understand what is exactly meant when I say things such as "left", "right", and "center". Trump was harshly anti-immigrant during his election campaign, starting off his first speech by calling Mexican immigrants rapists and drug dealers while calling for harsher immigration laws. The wall, and other deportation and immigration regulations, was his policy position on immigration. Clinton's position on immigration is best summarized by saying "I won't build a wall". This is still the Democratic party's position on the wall, "don't build the wall". It's not a policy position, its just saying that you aren't the other guy.
The political center has no policy position. Voters want to see politicians put forward tangible policy that they can then try to understand the effects it will have on their lives. Bernie Sanders began the 2016 election as an outsider candidate with little chance of challenging Clinton. He was able to quickly build a political coalition of inspired young voters precisely because he put forward tangible policy that people could get behind. He coined the term "Democratic Socialism" to quickly create a stopgap to give a name to his policy positions and supporters. He was effectively the true "left" candidate that rivaled the "right" that was Trump. He created the only real policy that stood opposite that of Trump.
This is where the future of the Democratic Party lies. For every "right" policy position that the GOP and conservative politicians put forward, the Democratic Party and liberals must put forward an equal and opposite policy position. Being an "opposition party" and a party of "we aren't them" will not win elections. The Democratic Party must learn this lesson, the party must move to the "left".