They've all come to look for America.

In what might be Senator Bernie Sanders' most revolutionary move yet, he released one final TV ad before the critical Iowa Caucuses that hits the high notes in all the right ways.

In the 24/7 lightning round of political attack ads, it's rare to find one that's a minute long but feels like 20 seconds, conveys a powerful message without saying a word, and reaches a key target group of people (baby boomers) by using a classic song from the '60s that they will instantly know.

Whatever you think about his politics, you've gotta admit: the underdog has the momentum now to surprise everyone.

The only words spoken in the entire ad?

"...I'm Bernie Sanders, and I approve this message."