The federal government Tuesday granted Maine a waiver of a key provision in President Obama's health care overhaul, citing the likelihood that enforcement could destabilize the state's market for individual health insurance. The U.S. Health and Human Services department said in a letter that it would waive the requirement that insurers spend 80 cents to 85 cents of every premium dollar on medical care and quality improvement. Instead, the letter said, the state could maintain its 65% standard for three years, with the caveat that HHS intends to review the figures after two years. The decision makes Maine the first state to receive a waiver of the requirement. Similar requests are pending from Kentucky, Nevada and New Hampshire.