A jury has convicted an anti-tax advocate on charges of evading state taxes, filing a false return, attempting to influence a public servant and failing to file a return between 2005 and 2007.Prosecutors accused Douglas Bruce of not paying taxes on $178,000 in interest gained on the millions he deposited into the anti-tax charity that he operated and which he used to support ballot initiatives.The government said Bruce's nonprofit, called Active Citizens Together, was set up for the sole purpose of hiding his income funding his anti-government activism.Bruce, a cantankerous government gadfly who frequently clashes with public officials, said the tax evasion case against him was politically motivated. Bruce said he did not make money from his ACT nonprofit and that state officials are going after him for promoting smaller government. He said he would appeal the conviction.Bruce is a former state lawmaker. He wrote the Colorado's Taxpayer's Bill of Rights.Bruce faces up to six years in prison and fines up to $500,000, prosecutors said. He will be sentenced in February.