AS ANYONE who watches Sunday’s Super Bowl will note, the demand for erectile-dysfunction drugs has not emerged in a vacuum. The manufacturers of Viagra, Levitra and Cialis have been bombarding sporting-event telecasts with advertising for their highly profitable drugs. In announcing this week that the new Medicare prescription-drug benefit would cover such erectile-dysfunction pills, the Bush administration said it had no choice but to include drugs that have been found to be “medically necessary” and approved by the Food and Drug Administration. At least one member of Congress, Steve King, R-Iowa, said he would introduce a bill to prohibit Medicare payment for Viagra and other “lifestyle drugs.” We get nervous any time politicians start trying to regulate what should be medical judgments. A ban would be ill-advised; it could become a dangerous precedent. But the prospect of taxpayers covering what could be costly and nonessential drugs -- at least in some cases -- underscores the Bush administration’s overall industry-friendly approach to this upcoming benefit. At the very least, the administration should adopt some reasonable cost controls on impotence drugs, such as those adopted by HMOs -- by limiting the number of prescriptions per beneficiary and by bargaining hard for discounts.