WASHINGTON (Reuters) - Democratic White House candidate John Kerry slammed his Republican critics as "crooked" liars on Wednesday and met former rival Howard Dean to discuss working together to beat President Bush in November. Kerry and Dean, bitter rivals in the Democratic primaries, met for an hour in Washington after Kerry returned from Illinois, where he criticized Bush's economic record and renewed his promise to repeal tax cuts for the wealthy and boost tax relief for the middle class. Kerry told a worker in Chicago that he was ready to fight back against his Republican foes, adding in an exchange...