Koch brothers affiliate Americans for Prosperity is spending big in the race for Virginia governor, targeting Democrat Ralph Northam with $1 million or more in mail and digital ads. They’re even attacking Northam for supporting a bipartisan bill under a Republican governor: The latest push includes a mailer that blasts Northam for supporting an increase in taxes on sales, gasoline and home and car purchases. It refers to sweeping 2013 legislation to raise revenue for transportation and road projects that was supported by then Republican Gov.