Sen. Barack Obama, bidding to become the first black president of the United States, won the Iowa caucuses Thursday night, defeating Hillary Rodham Clinton in the crucial opening test in the race for the 2008 Democratic nomination. In the Republican race, Mike Huckabee, a Baptist preacher turned politician, rode a wave of support from evangelical Christians to victory. Huckabee handily defeated Mitt Romney despite being outspent by tens of millions of dollars. Just months ago, Huckabee was virtually unknown outside Arkansas, where he had served as governor. Obama, 46 and a first-term US senator from Illinois, eased past a high-powered field that included Clinton, a senator and wife of former President Bill Clinton. He also beat former Sen. John Edwards of North Carolina, the party's 2004 vice presidential nominee.