It is a crime to threaten the President (18 U.S. Code § 871), President-Elect, Vice-President, and Vice-President-Elect. The Secret Service takes this seriously. You will get an opportunity to explain yourself to them if you indulge in threats like the ones mentioned in this news article.
Pro-Tip: The Hillary Defense™ will not help you. In a real court case there is no proof of intent necessary, the commission of the crime is enough.