McConnel’s obstructionism and Trump’s birtherism were obnoxious but they didn’t destroy Obama’s agenda. Failure to push for card check, Medicare for all, voter registration, prosecuting Wall Street fraud and war crimes, new trade deals, authorizing the extra-judicial murder of US citizens, and overthrowing the government in Guatemala, Ukraine, and Libya were the real disasters.He also notes that, "In 2008, Obama was really popular and he had the support of his own party. Obama failed to ram through his agenda because he refused to rally the people who put him into office."
There is a saying in politics, that Republicans fear their base, and Democrats hates their base.
Obama is a fairly strong argument for the final clause in that statement.