We’ve all heard the old saying, “Politics makes for strange bedfellows.” Considering that with the presence of Donald Trump the Republican race for the White House has become certainly strange and unpredictable, and now it will feature two candidates uniting for an event in September.

Donald Trump announced today at a press conference in South Carolina that he and Ted Cruz will be holding a joint rally to protest Obama’s nuclear deal with Iran.

Short of a national emergency, such as the attacks on 9/11, I can’t recall when two political rivals ever united in a common cause. But then again, I can’t recall a Presidential race as capricious as this one has been.

The rally will be held on Capitol Hill’s west lawn on September 9, and is being organized by the Tea Party Patriots, the Center for Security Policy, and the Zionist Organization of America. Cruz is set to be the keynote speaker, and has invited Trump to the rally. Both men have lambasted the Obama administration for the Iran deal.

So why the chumminess between these political rivals?

Trump has refrained from launching his trademark withering criticisms at Cruz, and in turn Cruz has avoided taking shots at Trump. “Many of the Republican candidates have gone out of their way to take a two-by-four to Donald Trump. I think that’s a mistake,” Cruz said.

Is Trump courting Cruz as a possible running mate? Or, as Tim Alberta at National Journal has theorized, does Cruz think Trump may help him win?