"Someone earlier made a remark about losing 500 soldiers and 2,200 wounded in Iraq. Those soldiers were sent there by the vote of Sen. Lieberman, Sen. Edwards and Sen. Kerry. I think that is a serious matter"

Howard Dean's quote is a criticism of the votes of Senators Lieberman, Edwards, and Kerry to send soldiers to Iraq. He is suggesting that their votes were careless which they must be held accountable for the losses of 500 soldiers and 2,200 injured in Iraq. He is emphasizing the gravity of the scenario, suggesting that the death is a severe matter that must not be ignored. He is likely trying to draw attention to the effects of the senators' votes and to motivate them to take more responsibility for their choices. His words are a suggestion that the decisions of politicians have genuine and often disastrous consequences.