Sens. Bernie Sanders and Elizabeth Warren will go head-to-head on July 30.

There are no two top, or even middle-tier candidates, with so much in common.

Yes, they are drawing support in the polls from different demographic pools, but that doesn't mean those voters aren't drawn to them for similar reasons.

The candidates seem to be taking a similar view: both have done their best to avoid any kind of confrontation, real or perceived, perhaps believing that the an attack on one could depress their own support.

For that reason, it will be incredibly interesting to see them share a debate stage. There's every chance what's effectively been a nonaggression pact will survive a debate night — with the pair using the platform to advocate for their mostly similar platforms.

Or...

Things could go a different way. If Sanders is worried that Warren is claiming the progressive mantle from him, he could question Warren on health care, and force her to talk more about Medicare for All.

If Warren — who said "I'm with Bernie" on health care the first time around — seeks to differentiate herself, she could argue that she's a better choice, plans and all, to make their shared proposals a reality.