Depends on the Context

Interesting point made by DeLong in one of his Socratic dialogues that he pulled from his archives. Krugman has made this point repeatedly in his columns and blog posts when he says that we're in a "liquidity trap" or unique circumstances. A convenient aspect of the Internet is the ability to go back a year into the archives and see that DeLong and Krugman were proven correct.

DeLong writes:

Adeimantos: Once again back to Hicks (1937). When the unemployment rate is high and the nominal interest rate on Treasury bonds is very very slow, adjustment comes in the form mostly of changes in spending and only slightly in changes in interest rates--the world is then "Keynesian." But when the unemployment rate is normal or low and the nominal interest rate on Treasury bonds is near its normal levels, adjustment comes in the form mostly of changes in interest rates and only slightly in changes in spending--the world is than "Classical." That's why the title of the article is "Mr. Keynes and the 'Classics'."