IDIOMS

do-or-die

(idiomatic) Requiring a determined or desperate effort to avoid the consequences of failure.

Example: 1996 Oct. 14, "Clinton v. Dole: Let the Debates Begin," Time:
  Clinton and Dole brought different needs to the debate. For Dole it was do or die. He had to hit Clinton hard but without seeming harsh, a conundrum for him all year.