WHEN PUSH COMES TO SHOVE

when or if push comes to shove: when or if matters are ultimately confronted or resolved; when or if a problem must be faced; in a crucial situation:

“If push comes to shove, the government will impose quotas on imports.”
"When the pressure is on; when the situation is critical or urgent; when the time has come for action, even if it is difficult)
“He's not an extremely talented builder, but when push comes to shove, he can usually get the job done.”

Traduções sugeridas: “na hora do aperto”, "quando o caldo engrossa", "quando a coisa fica preta" ou "quando o bicho pega" ou “quando a água bate na bunda...” quando não há saída, quando não há outra solução, no frigir dos ovos (se correr o bicho pega; se parar o bicho come) (catch 22?)
Sources: Dictionary/Wikipedia/Lista “tradutores@yahoo”