Prof. Brad Delong, liberal UC Berkeley Econ professor and frequent blogger, often calls for Bush to be impeached and the MSM to be replaced with something that reports the truth. He is pretty "progressive", although within the mainstream of Econ Profs, who are not typically real "lefties".
Delong looks at the candidates' fiscal stimulus plans to fight an upcoming recession and proclaims Obama's to be the best. Why? Well, you could read it yourself or I summarize on the flip.
Monetary policy, run by "the Fed", can inject money quickly into the economy to fight recession. Fiscal policy involves increased spending by the gov't. The classic problem with fiscal policy in fighting recession is that by the time the Congress and the President agree on something, the time for most effective action is often long past.
Now, Obama's plan is to quickly cut checks and put them in the hands of taxpayers. Edwards and Clinton also promise a laundry list of other useful programs. But Delong's point is those programs are terrible ideas as fiscal stimulus because they will take a long time to enact. (They are good ideas for other reasons.)
Now Krugman, not an Obama fan, thinks the lack of a laundry list in a stimulus plan shows Obama to be less progressive in his heart. Delong emphasizes that Obama's plan responds to the real-world problem at hand, not to the "problem" of political positioning. (Obama does propose similar programs elsewhere, but not as part of a "stimulus package.")
And "there's the beef" on this particular issue.