It's no secret that large numbers of progressives or left-liberals (or whatever label one prefers) are unhappy with Pres. Obama's performance. Although there are some grounds for that unhappiness, I think part of its source may be the high expectations generated by the 2008 campaign. But presidents, especially in recent years (and with the possible exception of G.W. Bush), never behave in office exactly the way their campaigning suggests that they might; they move to the center, for lack of a better phrase, and when the center itself has shifted, or is perceived to have shifted, that will produce disappointments (e.g., in Obama's case, the insufficiently large stimulus package, compromise on Bush tax cut extensions, certain questionable foreign policy decisions, etc.). The disappointments, however, should not obscure the real, if measured, achievements of the Obama admin (e.g., health care reform, saving the domestic auto industry, fulfillment of pledge to end U.S. combat ops in Iraq, two pretty good Supreme Court appointments, etc.). Obama has not changed the underlying structure of the U.S.'s 'winner-take-all' politics (Hacker/Pierson's phrase), but changes to this kind of entrenched system are difficult, to say the least.
Disenchantment with Obama on the left can produce some unhinged judgments, as in this comment from a recent CT thread:
Historical footnote: On March 25, 1968, roughly a week before he announced he would not seek re-election, LBJ was advised by the so-called Wise Men (elders of the foreign policy establishment including Acheson, Lovett, McCloy) to change tack and start de-escalating (and negotiating). For ultra-hawk Walt Rostow, Johnson's national security advisor, this represented the 'death' of the U.S. foreign policy establishment (see D. Milne, America's Rasputin: Walt Rostow and the Vietnam War , p.222). It was more like the establishment finally coming to its senses.