The Donald Trump Twitter publicity machine put out a threat to sue Ted Cruz over his eligibility. One photo that appeared in response:
It seems on the surface that a competitor in a political race can reasonably claim harm from an ineligible opponent—it hurts their chances of getting elected and the courts have recognized what they call “competitive standing.” See Tex Dem. Party v. Benkiser, 459 F.3d 582, 586-87 & n.4 (5th Cir. 2006); Schulz v. Williams, 44 F.3d 48, 53 (2d Cir. 1994); Fulani v. Hogsett, 917 F.2d 1028, 1030 (7th Cir., 1990).
Showing an injury in fact, however, is not the only requirement for standing. Another requirement is that the Court must be able to grant the relief requested. We do not know what a hypothetical Trump v. Cruz lawsuit would demand, but at a minimum it would include a declaration that Ted Cruz was ineligible to be president. If, as some judges have suggested (see, for example, Keyes v. Bowen 189 Cal.App.4th 647, 661 (2010)), the definition of natural born citizen is delegated to Congress in certifying the vote of the electoral college, then courts may well be unwilling to grant even a declarative judgment for or against Cruz.
In the unlikely event Trump brought a lawsuit, and in the unlikely event that he won some judgment against Cruz, and appellate court could simply reverse the lower court, saying “you can’t do that” and avoid any resolution of the Cruz eligibility question. In my opinion, Trump is no more likely to sue Cruz than he is to shoot someone on 5th Avenue.
I think it nearly certain that Trump will never sue Cruz because he would likely lose the suit, and that would make him look bad.