WASHINGTON - President Bush tried to steady his presidency yesterday by urging Americans to support the Iraq war for the long haul, but a bigger boost for a limping White House may have come from a rogue Democrat. As promised, Bush launched another political offensive aimed at resurrecting his slumping agenda and rebuilding support for an increasingly unpopular war. The four-week strategy, which he previously tried with some temporary success in December, began with a speech aimed at linking the war on terrorism to Iraq - this time without Bush uttering unfounded optimism. "I wish I could tell you that...