Here’s why the ad is important. To get immigration reform that includes a path to citizenship through the Senate, groups like Zuckerberg’s have to prove that voting for it won’t be viewed as apostasy among the conservative community. (Remember that the 2007 immigration reform bill was done in by strong opposition from conservative talk radio.)

To do that, a case for the conservative bona fides of the likes of Graham (as well as other potential “yes” votes on the Senate Judiciary Committee including Orrin Hatch, Chuck Grassley of Iowa and Jeff Flake of Arizona) has to be made over an extended period of time. And that case is entirely disconnected from the immigration issue.

What these ads aim to do is lay a foundation so that when their senator is weighing whether to vote for immigration reform, conservatives in the state will think to themselves: “I may not agree with him (or her) on this, but they stand up to Obama on lots of other things.”

It’s a smart strategy by Zuckerberg’s group since the past few elections have given Senate Republicans plenty of reason to be afraid of opening up any room on their ideological right flank.