As you can see in the above chart, two factors—repealing Obamacare’s individual mandate and the CBO’s outdated March 2016 baseline—explain nearly all of the CBO-scored coverage difference between GOP bills and Obamacare.

It’s why the various Senate tweaks to the Better Care Reconciliation Act—repealing fewer of Obamacare’s tax hikes, say, or throwing $45 billion at opioid addiction—have no impact on the CBO’s coverage estimates.

Some Republicans advocate starting over and writing an entirely new Obamacare replacement that can get a better CBO score. But any replacement that repeals the individual mandate will be scored by the CBO as covering at least 16 million fewer people—and probably worse.