grab at a straw

1. To assert or come up with something that lacks any credibility, especially as a desperate bid to achieve something or convince someone. A: "But what about all those times I took the trash out when you hadn't even asked me to?" B: "That has nothing to do with why you're in trouble now, so stop grabbing at a straw." The government is really grabbing at a straw now in its attempt to defend the controversial legislation. It's almost sad to watch how poorly that candidate is doing in the debate. He keeps bringing up his previous successes in every answer, but clearly he's grabbing at a straw.

2. To consider or reach for any kind of help or solution in a bad situation. A: "I've started going to a psychic to help me figure out how to salvage my marriage." B: "I think you're grabbing at a straw, Mike." Just because he's remorseful, don't grab at a straw and convince yourself actually loves you. He did cheat on you, after all! I know I'm probably grabbing at a straw, but I need to find hope in something, anything! I refuse to accept this dire diagnosis.