(CNN) -- With this year's goal for enrollment in Obamacare seemingly out of grasp and the President under renewed partisan attack over the program, an official key to implementing it has resigned.
Gary Cohen leads the agency that made many of the rules for the Affordable Care Act and established the Marketplaces, where Americans can buy health insurance through Obamacare, including Healthcare.gov, according to a statement Wednesday announcing his departure.
The Marketplaces came under fire, when they crashed massively upon rollout.
Cohen will vacate the post of Director of the Center for Consumer Information and Insurance Oversight after March 31.
That's the day open enrollment runs out, and with a goal of 6 million signups, the ACA has only 4 million on the books so far.
February saw 700,000 new enrollments, and to meet its goal, Obamacare would have to garner a record monthly number of new enrollees.
The agency statement did not mention a reason for Cohen's departure but indicated that family matters may have something to do with it.
He will be replaced by physician Mandy Cohen, who is currently serving in another leadership position at the CCIIO.
A Republican lawmaker latched onto data from a recently released ACA report to beat up Obama once more.
Rep. Ann Wagner, R-Missouri, cited a "quietly-released report" from the Centers for Medicare and Medicaid Services, the agency over the CCIIO, that claimed 11 million people would face higher premiums because of the healthcare law.
The CCIIO is also responsible for implementing measures concerning private health insurance.
Wagner repeated past accusations that Obama mislead the public over ACA's costs.
"It's another slap in the face to our already hurting middle class," she said.
Obama countered, saying that, despite the "disruptions" in the ACA's rollout - including the much-maligned website debacle - the law is a success. The President also said that the Republican fixation on blockading the law's progress bordered on farce.
CNN's Kevin Bohn contributed to this report