For Trump and GOP, 'Obamacare' repeal is complex and risky

[...] approve legislation restructuring the nation's huge and convoluted health care system — despite Republican divisions, Democratic opposition and millions of jittery constituents.

Trump and congressional Republicans will be under intense pressure from their core conservative supporters to repeal Obama's 2010 health care law — and fast.

While the replacement effort is underway, Republicans will risk aggravating up to 30 million people who are covered by the law or buy policies with prices affected by its insurance marketplace.

Seemingly acknowledging that two-step process, Vice President-elect Mike Pence said Sunday on "Fox News Sunday" that Trump "wants to focus out of the gate on repealing Obamacare and beginning the process of replacing Obamacare."

Because Republicans will control the Senate by just 52-48, Congress will first have to approve special budget procedures to prevent Democrats from stopping repeal legislation by filibuster.

Republicans, for example, would need a simple Senate majority to end IRS penalties against people who don't buy insurance but would still need 60 votes — requiring Democratic support — for other changes such as raising limits on older people's premiums.

Congress and Trump might repeal Obama's law, but while they're laboring on a replacement, nervous insurance companies begin pulling out of markets and raising premiums.

Obama's law mandates coverage for individuals because without that requirement many healthy people would forgo policies, driving up costs for everyone else and destabilizing insurance markets.

Ryan has proposed shielding people from higher premiums if they've had "continuous coverage," allowing higher rates for people who have not had policies, but Republicans have yet to decide how to keep insurance markets viable.