Looks like the FBI wants the courts to overturn (or ignore) Watts v. United States:

Petitioner’s remark during political debate at small public gathering that if inducted into Army (which he vowed would never occur) and made to carry a rifle “the first man I want to get in my sights is L. B. J.,” held to be crude political hyperbole which in light of its context and conditional nature did not constitute a knowing and willful threat against the President within the coverage of 18 U.S.C. 871 (a).

…a statute such as this one, which makes criminal a form of pure speech, must be interpreted with the commands of the First Amendment clearly in mind. What is a threat must be distinguished from what is constitutionally protected speech…