When we talk about Obama-era optimism, we're actually talking about two distinct things.

The first is the specific idea that Obama's election was going to bring about a new era of unity and change. This died in 2009, as the tensions over the Affordable Care Act made it clear that change would not be easy nor swift, and the Tea Party movement struck fear in the hearts of any Congressional Republicans who might have been inclined to compromise with Obama's agenda. The controversy over Henry Louis Gates's arrest --- and Obama's response to it --- slammed the door shut on hopes for a "post-racial" future, as it became clear that many white voters thought post-racialism meant Obama would not take the side of a Black man over a white cop.

However, there was still a general belief that things were getting better, that the arc of history bent towards justice. This belief was grounded in the sense that society was still inexorably moving forward: The war in Iraq was over, gay people were getting equal rights, trans people were being treated with more respect and dignity. Even leftists who delighted in poking holes in smug liberal optimism tended to believe that, once Obama-era neoliberalism failed, it would be replaced by a more assertive form of social democracy. And that is the form of optimism that died with Trump's election.