Obama was a great presidential candidate. He maximized the Democratic vote. But when he wasn’t on the ballot in 2010 and 2014, Democrats lost badly. Their turnout machine didn’t work as effectively without him on the ticket. So the Democratic coalition will probably be less broad in 2016.
Democrats think they have a number of current issues on their side. But issues that poll well don’t always cause voters to back candidates of the party associated with those issues. Raising the minimum wage is a good example. It’s clearly a Democratic issue. In November, voters in Arkansas, Nebraska, South Dakota, and Alaska backed increases in the minimum wage. At the same time, they elected Republicans to the Senate—and by large margins except in Alaska.
Among the major Democratic issues today are global warming, same-sex marriage, abortion, and voter ID. Global warming is so far down the list of issues that voters care about, it has dropped out of sight. The fight over gay marriage is over. Democrats benefited in two election cycles from blaming Republicans for a “war on women” involving abortion and contraception. That issue died in 2014. Opposing voter ID laws may galvanize African Americans and the party base, but that’s it. Besides, there’s no evidence such laws prevent voting.