Black Lives Matter has been a movement since all the way back to Trayvon Martin. Have Dems been losing elections since then?

When Obama won, there was a shift in party identification

“The Obama administration was not only eight years of a Democratic president — which meant that partisan polarization would only continue to grow — but also eight years of a black president,” write Sides, Tesler, and Vavreck. “Once Obama was elected, Americans’ racial identities and racial attitudes became even more potent political forces. The gap between the political opinions of whites and blacks grew larger.”

The size of the changes, and the way they mapped onto party politics, were stunning:

In Pew Research Center surveys from 2007, whites were just as likely to call themselves Democrats as Republicans (roughly 44%-44%). But whites quickly fled the Democratic Party during Obama’s presidency. By 2010, whites were 12 points more likely to be Republicans than Democrats (51%-39%). By 2016, that gap had widened to 15 points (54%-39%).

This, um, white flight was concentrated at the bottom of the education ladder. “Whites who did not attend college were evenly split between the two parties in Pew surveys conducted from 1992 to 2008,” write the authors. “But by 2015, white voters who had a high school degree or less were 24 percentage points more Republican than Democratic.”

Nor was this just the reverberations of the financial crisis leading to easily misinterpreted changes among voters. The data included survey questions about racial attitudes, and they were revealing. 

“No other factor predicted changes in white partisanship during Obama’s presidency as powerfully and as consistently as racial attitudes,” the authors write. “Nor was the racialization of partisanship merely a byproduct of whites’ changing their racial attitudes to match their views of Obama. Racial attitudes that were measured before Obama became president predicted subsequent changes in party identification when these individuals were re-interviewed during his presidency.”

https://www.vox.com/policy-and-politics/2018/11/5/18052390/trump-2018-2016-identity-politics-democrats-immigration-race

When Hillary lost, many blamed identity politics. Mark Lilla's 2016 NYT article was a classic example.

https://www.nytimes.com/2016/11/20/opinion/sunday/the-end-of-identity-liberalism.html

Blame for down ballot losses is now placed on Black activists. Black activists are not going to stop seeking justice. No matter how equal justice is packaged, it will not be the "right" message for many people.