WASHINGTON - Call it the campaign with no margin for Republican error, in a nation that is war-weary and eager for change, yet seems wary of the Democratic option. Even Republicans tacitly concede they will lose seats in both the House and Senate in Nov. 7 elections midway through President Bush's second term. Yet Democrats, long out of power, are loath to predict publicly they will gain the six Senate and 15 House seats they need for control of Congress. Voters like Jim Meyer are part of the reason one party is scuffling, yet the other not completely confident. "I...