Former presidential candidate Bill Richardson endorsed Democratic frontrunner Barack Obama Friday, citing his call to overcome the country's racial divisions and urging the party to shift gears to November's general election, according to dpa. Richardson, the governor of New Mexico who dropped out of the Democratic race in January, wrote in a letter to supporters that it was Republican candidate John McCain who should now be the focus of the Democrats' energy. "It is time ... for Democrats to stop fighting amongst ourselves and to prepare for the tough fight we will face against John McCain in the fall," Richardson said in a statement posted on Obama's website. Richardson is the highest profile former Democratic candidate yet to make an endorsement. The move comes a blow to Senator Hillary Clinton, who along with her husband Bill Clinton had reportedly been lobbying hard for Richardson's support since he left the race. Richardson said that, as a man of Hispanic origin, he was especially touched by a critical speech Obama gave Tuesday on race relations. Obama is vying to become the first African-American president. "Senator Obama has started a discussion in this country long overdue and rejects the politics of pitting race against race," Richardson said. "His words are those of a courageous, thoughtful and inspiring leader, who understands that a house divided against itself cannot stand." Richardson was to formally endorse Obama at a campaign event in Oregon later Friday. Obama leads Clinton in the battle for delegates to the Democratic Party nominating convention in August.