make a federal case of

make a federal case (out) of (something)

To exaggerate or build up the importance of something; to make a big deal out of something. The phrase is often used to complain that someone is exaggerating a problem or alleged wrongdoing. So I ate your leftovers. Geez, don't make a federal case out of it! I'm not trying to make a federal case out of it, but I know you stole my new sweater!
See also: case, federal, make, of
Farlex Dictionary of Idioms.

make a federal case of

Also, make a big deal of. Give undue importance to an issue, as in I'll pay you back next week-you needn't make a federal case of it, or Jack is making a big deal of filling out his passport application. The first hyperbolic expression, almost always used in a negative context, alludes to taking a legal action before a high (federal) court. The second alludes to an important business transaction (see big deal, def. 1).
See also: case, federal, make, of
The American Heritage® Dictionary of Idioms by Christine Ammer.
See also:
  • (someone or something) promises well
  • all right
  • a/the feel of (something)
  • (I) wouldn't (do something) if I were you
  • (have) got something going (with someone)
  • (you've) got to get up pretty early in the morning to (do something)
  • a straw will show which way the wind blows
  • accompanied by
  • accompanied by (someone or something)
  • accompany