@snood,
I'm inclined to agree with you, and to doubt Edgarblythe's expressed optimism. Obama rode a tide of support in 2008 from a fairly broad spectrum of the electorate and, at least during his first term, enjoyed commanding majorities in both houses of Congress. That doesn't always occur with new Presidents in their first terms. Some say he wasn't forceful enough in pushing change during that time.. However, the fact that the balance of power in the Congress shifted significantly after his first term suggests that he paid a political price for the changes he did make.We'll never know what might have been the result had he pushed harder and faster for more during those first four years. Obamacare was a very contentious issue, and I'm not confident he could have achieved a lot more.
After the Republicans captured the House his maneuvering room was very limited. It would be hard to accuse him of not trying and not exercising all the discretion (and perhaps more) the Constitution gave him during the current term.
The intensity of Sander's appeal to a segment of Democrat voters is undeniable, and it is a safe bet he will get broader support among Democrats if he wins the primary (though I expect the Clintoins will not walk off the stage quietly). That said I don't see him getting a level of siupport in the new Congress even equal to what Obama enjoyed in his first term. The New World Bernie is promising contains many features that are much opposed among many voters, and the likelihood of a Democrat Majority in the House big enough to achieve that appears very dim to me. I believe Bernie's New World will be an even steeper hill to climb than Obama's.