Specify.
There’s no reason to rehash his history but since you asked, these are the most obvious:
https://www.huffingtonpost.com/entry/chickenshit-club_us_5963fcc6e4b005b0fdc7bacb
That’s why we have free speech!
Obama had the chance to be a transformational President, but he was an incrementalist, and he failed miserably at the politics of building the Democratic Party and a progressive movement. His vaunted economic recovery worked mostly for the wealthy, and Obamacare was a weak Republican health insurance plan that still left 24 million uninsured.
As his closest and most experienced advisor, Biden shares much of the blame. Obama came to office with very little experience at national politics, and Biden and Emmanuel both failed to advise him competently.