It would be the health insurance industry’s worst nightmare: if the Supreme Court strikes down the requirement that individuals obtain coverage but left the rest of President Obama’s signature law intact. Most concerning to insurers, they say, would be the continued requirement that they cover people with pre-existing medical conditions without charging the sickliest higher premiums. Insurance premiums could rise up to 40 percent, making it prohibitively expensive for people to afford coverage, according to several analyses of that scenario. Millions of employers would drop insurance coverage. And tens of millions more would remain uninsured - the very problem health reform tried to address.