JUDY WOODRUFF:

Finally tonight, a look at some of the backstory to this year's raucous political season.

Just as it brought to the surface tensions and disaffection within the Republican Party, so too have divisions in the Democratic Party revealed themselves.

Author and historian Thomas Frank explores all this in his latest book, "Listen, Liberal."

I sat down with Frank recently in our studio.

Thomas Frank, welcome to the program.

THOMAS FRANK, Author, "Listen, Liberal": Good to be here, Judy.