WASHINGTON (AP) - Senate Democrats demanded Thursday that President Bush order a halt to personal attacks on the party's leader, Sen. Harry Reid, and expressed regret they had failed to mount a stronger defense for his defeated predecessor. "This is a new Democratic party," Sen. Chuck Schumer, D-N.Y., said at a news conference called to release a letter telling Bush to muzzle his "political operatives." "...It says to the president, 'you will not intimidate us'," added Schumer, who likened the attacks on Reid to political knee-cappings. The letter itself was written in milder terms. "We urge you to keep your...