In March 2010, days before former President Obama signed his healthcare legislation into law, the Congressional Budget Office estimated that by 2017, 23 million people would be obtaining insurance through the program's exchanges. In a new report issued Tuesday, the CBO said that the actual number for 2017 would be 10 million, or less than half of that.

The new projections by the CBO come at the start of a heated debate over repealing and replacing Obamacare. The relatively low enrollment numbers (and specifically the difficulty that insurers have had signing up young and healthy individuals to offset the cost of covering older and sicker enrollees) have dogged Obamacare. Money-losing insurers have raised premiums, narrowed choices of doctors and hospitals, and in some cases, exited markets altogether.

In addition to highlighting how Obamacare's exchanges missed expectations, the CBO report gives ammo to Republicans who have been arguing that people shouldn't place too much stock in CBO coverage projections regarding any replacement plan, given that bean counters were so off in estimating the coverage effects of Obamacare. By 2017, CBO had originally projected that 21 million would remain uninsured. But the number is now estimated to be 27 million.

Projecting out further, the CBO said that by 2027 (which would be the 14th anniversary of Obamacare's implementation), 13 million individuals would be obtaining insurance on the exchanges. But at the time of passage, the CBO projected that Obamacare would reach that milestone in 2015 — or year two.

In addition, the report projected that if it isn't changed, the law would cost the federal government more than $1.9 trillion over the next decade for spending on the exchanges and expanding Medicaid. (This money is slated to be offset by Obamacare's higher taxes and cuts to Medicare).

With all of this said, Democrats are likely to point to other aspects of the report to pound home their message of opposition to Obamacare repeal.

The report said that as of 2017, the law is responsible for covering 12 million with Medicaid and providing subsidies to nine million individuals to purchase insurance on the exchanges. All of those people would be in danger of losing coverage if the law were to go away (many of them in states won by President Trump) providing a powerful political tool to use against Republicans.