400 dead Americans
Let's run the numbers.
If the Iraq war supplemental passes then Bush will have his war, free and clear, at least through September. Let's call that an even four months of unhindered war.
The first four months of 2007 saw 348 U.S. casualities, and this was before Bush's escalation has taken full effect. So we can expect the casualty rates to be even higher in the next four months.
This means that approximately 400 American service men and women will die before the next chance arrives to do anything to reign in Bush's folly.
That is what voting for this measure means.
400 more dead Americans.