Dagnabbit! A metaphor, not counting puns, is not a comparison. That’s a simile. In a metaphor, the subject IS the other thing, or BECOMES the other thing.
Simile: Egbert has really filled out; he looks like Horton the Elephant.
Metaphor: Woo, look at Egbert; he’s Horton the Elephant.
Simile: Lobelia is quiet as a mouse.
Metaphor: That Lobelia, she’s such a mouse.
Simile: Reynolds looked like a deer in the headlights.
Metaphor: Reynolds was a deer in the headlights.
Metaphor: This proposal is a toothless tiger.
Now, you can resume the punfest. The tooth is out there.
Er. So, I suppose I am the only one who thought that was actually pretty funny? Look, Harry Reid isn’t one of life’s funny people (from what I have seen); let him have this one.
How do you pronounce “metaphor”? Actually I don’t think it works that well in American pronunciation either; “metaphor”-“meadow for” is a bit of a stretch.
I admit to occasionally saying a dumb thing or two. But I don’t call them “bad metaphors.” Granted, OP was right that it wasn’t particularly effective. He could’ve just said something like, “completely toothless.” And tigers have claws as well as teeth. Even a “toothless tiger,” or a tiger that has “less teeth than a toothless tiger,” can cause some harm.
Personally, I’ve heard much more egregious things said in both the House and Senate. For example, when they changed the name of “French fries” to “Freedom Fries” in the House cafeteria. The Rep who pushed that one is now against U.S. policy with Iraq. (I’d love a job like that; where you can do as little or a much as you want, and no one seems to see the difference.)