MEMO FLAP: Politics may be Washington's lifeblood, but the chairman of the House Energy and Commerce Committee, Rep. John D. Dingell, is insisting that proprieties be maintained. The Michigan Democrat is irate over White House memoranda supporting President Bush's reelection that recently were circulated to Department of Energy employees. . . . Dingell is demanding an investigation by the General Accounting Office into the incident. The material, which included White House-approved talking points on the economy and referred critically to Democratic nominee Bill Clinton, were circulated to DOE employees earlier this month by Ann W. Lavin, director of the department's executive secretariat. Dingell contends that the memos were "unabashedly political documents," and that their circulation may be a violation of the Hatch Act, which prohibits partisan political activity by federal employees. . . . A DOE spokesman said Dingell's complaint has been referred to the department's lawyers. But the congressman probably shouldn't get his hopes up. Noting that the documents were sent to the agency by the White House, the spokesman said he saw no reason why "their further distribution would be a violation of anything."