ORLANDO, Fla. — The dark-money nonprofit that worked with Republican strategists last year to promote spoiler independent candidates in important state Senate races in Florida also raised more than $700,000 from organizations controlled by Democratic fundraisers. The nonprofit, Grow United Inc., which is based out of a UPS Store in Denver, provided more than half a million dollars last fall that Republican strategists used to advertise little-known independent candidates who did no campaigning of their own in three key Senate elections — one in Central Florida and two in South Florida. The ads...