Restrained Foreign Policy - Idealism or Realism?

Back in my college days, I took a political science course that had me tied up in knots, because it repeatedly asked the question, "was the particular policy idealistic or realistic"?

In most cases, I was tempted to label policy idealistic, because you could point to a president having laid out a plainly ideological campaign platform. But the more I looked, the more policy seemed informed by events, to the point that I wanted to call it reactionary. Two examples:

FDR condemned Hitler's invasion, but didn't declare war on Germany until after Japan bombed Pearl Harbor, and Hitler declared war on the US subsequent to our declaration of war on Japan.

Lincoln was plainly an abolitionist candidate. But as president, he didn't talk about emancipation as a cause for war. It was in reaction to the Confederacy's attack on Fort Sumter, and an effort to preserve the Union. The Emancipation Proclamation isn't issued until after Gettysburg, and Lincoln the politician felt the time was at last right to bring it up.

I know that I even waver on the idealism/realism question with regard to my own foreign policy positions. Yes, I do subscribe to the 'no foreign entanglements, peaceful commerce with all' policy of George Washington as a matter of ideology. On the other hand, it seems to make so much sense to not pay out of American pockets to pay for the defense of Japan, Germany, and so many other nations capable of their own defense, merely as a practical matter- especially when the US is borrowing such vast sums from China and other nations, partly to pay for extra-national defense.

The Cato Daily Podcast for July 16th is an interesting listen. It mentions Russia in the pre-Georgia context, which really stirs up the idealism/realism consideration.

Here's the link to Cato's Daily Podcast archive. Click the item titled, "A Strategy of Restraint Overseas" to listen.

It just isn't easy to put these things into neat little categories.