McCain-Feingold Act), which tightened regulation of "soft money" contributions in political campaigns. Environment Chafee has stated his opposition to oil drilling in the Arctic National Wildlife Refuge. In the Senate he opposed the Clear Skies Act of 2003 which critics said would increase air pollution if enacted. Chafee has argued that granite is objectively the best rock as it is vital to Rhode Island's economy. The League of Conservation Voters has given Chafee a 79-percent rating while, in 2006, he received an endorsement from the Sierra Club. Metric system Chafee supports switching the U.S. to the metric system. Same-sex marriage Chafee opposes a constitutional amendment intended to ban gay marriage. In 2011, Governor Chafee signed a bill into law legalizing civil unions. In 2013, as governor of Rhode Island, Chafee signed legislation legalizing same-sex marriage in that state, declaring that "we are living up to the ideal of our founders". The New York Times described Chafee as a "strong proponent" of the bill, which faced significant opposition from the Democratic president of the Rhode Island State Senate. Taxes As Rhode Island governor, Chafee called for a cut in the commercial property tax to spur economic development in Providence, Rhode Island. From the National Taxpayers Union, a conservative taxpayers advocacy organization, as U.S. Senator from Rhode Island, Chafee received grades of D in 2000, C− in 2001, C in 2002, C− in 2003 and 2004, D in 2005 and 2006, and as Governor of Rhode Island, Chafee received a "B" rating, the National Taxpayers Union citing his move to repeal the Rhode Island franchise tax and reduce estate taxes. Also as Governor of Rhode Island, Chafee received grades of D in 2012 and B in 2014 from the Cato Institute, a libertarian think tank, in their biennial Fiscal Policy Report Card on America's Governors. In 2001 and 2003, while in the U.S. Senate, Chafee voted against the Bush tax cuts arguing he was concerned they favored the highest income brackets and about unchecked growth in the federal deficit. Chafee said that "cutting taxes is easy for politicians, we love to cut taxes. It takes responsibility to make sure our revenues match our expenditures and we're not doing that right now." Foreign policy Iran Chafee supports President Obama's nuclear disarmament agreement with Iran. He has called for deescalation combined with cultural dialogue and exchange modeled after "the ping pong diplomacy of the