WASHINGTON, Jan. 27 - Four unions filed suit on Thursday to prevent the Bush administration from carrying out the first phase of a personnel system that would give officials sweeping power to reward, punish and reassign federal employees. The suit was filed by career employees of the Homeland Security Department, challenging rules it issued on Wednesday. White House officials said the new procedures, affecting 110,000 employees, were a model for changes throughout the federal government. The unions asked the Federal District Court here to issue an injunction against the final rules, which will be published on Tuesday in The Federal...