the thing is...

the thing is

The main or fundamental issue or element (of what's being discussed). I agree with your point, but the thing is, if we agree to increase spending for education, then all sorts of other public utilities will go underfunded as a result.
See also: thing
Farlex Dictionary of Idioms.

the (only) thing ˈis...

(spoken) used before mentioning a worry or problem you have with something: I’d love to come — the only thing is I might be late.
See also: thing
Farlex Partner Idioms Dictionary
See also:
  • the thing is
  • the thing of it is
  • agree to
  • concur on (someone or something) with (one)
  • concur with (one) on (someone or something)
  • against the current
  • (Do) you feel (me)?
  • approve
  • approve of
  • come down to the wire