Somebody has finally put some numbers on what the Republican effort to undermine Obamacare will mean for everyday Americans.

Come 2019, the number of people without health insurance will rise by nearly 5 million, while millions more will enroll in short-term plans, according to Urban Institute research released Monday. The study is the first serious effort to assess the combined effects of several major health policy changes that President Donald Trump and his allies have made over the past year.

Those short-term plans will be popular because they are dirt cheap, relative to the usual price of health insurance. But thats only because they arent available to people with pre-existing conditions and leave out key benefits like mental health, maternity care and prescriptions which at least some of those beneficiaries will need when they get sick.

Meanwhile, some people who need or want more comprehensive coverage will have to pay more for it, as the study predicts premiums for such plans will rise 18 percent. And the federal government, which subsidizes plans for lower-income consumers through tax credits, will have to spend more money.

This is still a far cry from full repeal of the Affordable Care Act, which is what Trump and the Republicans tried to pass last year. But it represents a significant reversal of the changes that the 2010 health care law unleashed.

What Trump And The Republicans Have Done

One of the most significant recent policy shifts is the decision to end the individual mandate, which imposes a fine on people who could afford to pay for insurance but decline to do so. Trump signed tax legislation in December that ends the mandate starting next year.

But that is not the only big change Trump and congressional Republicans are making. Trump is using his executive authority to undermine Obamacares insurance rules , including those that prohibit insurers from declining coverage to people with pre-existing conditions , as well as some that require insurers to cover 10 essential benefits such as mental health, maternity and prescription drugs.

The most vivid example of this is a regulation the Trump administration formally proposed last week. It would allow insurers to sell short-term or limited duration plans that would last for up to one year. Such plans can deny coverage for pre-existing conditions and dont have to cover all of the essential benefits, engaging in the sorts of practices that the 2010 health care law sought to prohibit altogether.

These plans have existed for a long time. But they could not last for more than three months under regulations the Obama administration put in place and they would not count toward the individual mandate.

The rule didnt go into effect until in 2016, and some insurers already flout it by packaging together multiple plans so they last for a year. Still, with the mandate in place, the plans have mostly served a relatively small niche market: those with brief lapses in coverage.