By Phil Stewart WASHINGTON (Reuters) -The United States assesses that Russia is suffering failure rates as high as 60% for some of the precision-guided missiles it is using to attack Ukraine, three U.S. officials with knowledge of the intelligence told Reuters. The disclosure could help explain why Russia has failed to achieve what most could consider basic objectives since its invasion a month ago, such as neutralizing Ukraine’s air force, despite the apparent strength of its military against Ukraine’s much smaller armed forces. The U.S. officials, who spoke on condition of anonymity due to t…