Breitbart thinks this is a pretty good idea. They write:
Donald Trump told Fox News’ Greta Van Susteren Thursday night that he believes Sen. Ted Cruz should get a declaratory judgment from a federal court, ruling that Cruz is a natural born citizen eligible to run for president.
What Trump may not know—but which his lawyers should have told him—is that Cruz can only get such a ruling if Trump sues him first.
Breitbart News has thoroughly analyzed the legal issues raised by Trump’s questioning whether Cruz is eligible under Article II of the Constitution to run for president. If Trump sues Cruz now, this matter could be decided by a federal court before Iowans go to their caucuses on February 1.
Federal courts are powerless under Article III to act until someone with standing to sue files a declaratory-judgment lawsuit against Cruz. The clearest standing is the standing of a rival GOP candidate.
If Trump believes Cruz’s eligibility is in doubt and that Cruz should get a declaratory judgment to settle the matter, then Trump should sue now. Either way, he would do himself, Cruz, and the country a favor by doing so.