A 15-month inquiry by a top House Democrat has found that enforcement of the nation's food and drug laws declined sharply during the first five years of the Bush administration. For instance, the investigation found, the number of warning letters that the Food and Drug Administration issued to drug companies, medical device makers and others dropped 54 percent, to 535 in 2005 from 1,154 in 2000. The seizure of mislabeled, defective or dangerous products dipped 44 percent. The research found no evidence that such declines could be attributed to increased compliance with regulations. Investigators at the F.D.A. continued to uncover about the same number of problems at drug and device companies as before...but top officials of the agency increasingly overruled the investigators' enforcement recommendations. The investigation found that by almost every measure, enforcement actions had significantly declined from 2000 to 2005. Dr. Sidney M. Wolfe, director of the Health Research Group at the watchdog organization Public Citizen, noted that the agency now received about $380 million a year in fees from drug makers. "The public," Dr. Wolfe said, "is getting the kind of F.D.A. that the industry is paying for them to get."