Governor Vilsack vows to veto a bill which would force unions to ask memberseach year whether their dues may be used for political purposes. Republicans want the provision in a campaign finance reform bill as theG.O.P. believes republicans have been targeted by union-financed attack ads.Vilsack says state law already requires unions to get written permissionfrom members to use their dues for political work — and the law allowsunion members to get out of the deal anytime they wish. Vilsack says hisoffice has received seven-thousand pieces of mail since he took office, andnot one letter asked for the change republicans propose. Vilsack accusesrepublicans of playing politics by adding the controversial idea to a billwhich is needed to close a loophole in campaign finance law.