Rep. John Delaney shown in November 2012. (Katherine Frey/The Washington Post) (Katherine Frey/The Washington Post)

Six weeks ago, Rep. John K. Delaney began to push this idea: What if Maryland just abandoned its troubled online health insurance marketplace and used the federal version instead? Or maybe used some combination of the two?

Delaney (D-Md.) waited for state officials to fully evaluate the option. Then, on Jan. 6, he sent a letter to the state’s secretary of health and asked for a brief analysis of the “pros and cons” of switching. He didn’t receive a formal response. On Tuesday, Delaney sent another letter.

“I have asked the state, repeatedly, to provide a basic assessment of the costs and benefits of switching to the federal exchange,” Delaney wrote in the letter, which is posted on his Web site. “It is deeply frustrating that we continue to operate with so little transparency. This lack of openness is not serving the interest of the people of Maryland.”

That same day, Maryland Secretary of Health and Mental Hygiene Joshua M. Sharfstein sent Delaney a response, according to a copy of the letter released by the department. Sharfstein wrote that the governor recently decided not to partner with the federal exchange during the current open enrollment window, which runs until March 31, because the risks outweigh the potential benefits.

That announcement was made Jan. 14, the same day that Lt. Gov. Anthony G. Brown (D) testified before lawmakers about emergency legislation to assist Marylanders who tried to use the exchange but were left without coverage. Brown is in charge of implementing President’s Obama’s Affordable Care Act in Maryland.

Sharfstein wrote that there were three key considerations in making that decision: 1) Someone would have to build and test an interface that could pass Medicaid enrollment information from the federal site to a database to the state’s Medicaid system. 2) The insurance carriers would have to upload their plan data and ensure its accuracy, and take other steps to ensure that they properly received enrollment data from the federal marketplace. 3) Switching systems would be a challenge for Marylanders who have started an application in the current system.

Another factor in the decision, Sharfstein wrote: The CEO and president of CareFirst, the largest insurance carrier participating in Maryland’s exchange, strongly recommend that Maryland stick with its own site. Sharfstein said the CEO’s position is “particularly relevant” because the company is familiar with Maryland’s exchange and the federal one, and the company shares the goal of enrolling as many people as possible as quickly as possible.

Delaney said Tuesday afternoon that he had received the letter and was disappointed that it “did not contain much significant new information, other than to point out that the state is relying heavily on the advice of the CEO of CareFirst,” according to a message forwarded by his spokesman.

Delaney wrote in his letter to Sharfstein that “it is extremely troubling that major problems with the Maryland Health Connection persist.” Maryland’s enrollment numbers appear to lag behind those of all neighboring states, he wrote.

Between Oct. 1 and Jan. 11, state health officials said that 22,512 Marylanders enrolled in a private health plan through the exchange — far fewer than the state expected, as its goal was to enroll at least 150,000 by March 31. Additionally, the state has newly enrolled 29,517 in Medicaid. That’s on top of the 93,514 people who were automatically enrolled in Medicaid for this year when the state expanded its program.

O’Malley is now touting a new goal: enrolling 260,000 Marylanders in Medicaid or private plans by the end of March. So far, the tally is at 145,543.

There are also 60,000 Marylanders who have been deemed eligible for Medicaid. And more than 131,000 people have created identity-verified accounts in the exchange.

Delaney noted in his letter that over the weekend, state health officials announced that a few hundred Medicaid enrollment packages were sent to the wrong people. O’Malley has recently and repeatedly said that the Maryland exchange has dramatically improved and is superior to the federal marketplace when it comes to Medicaid enrollments.

Delaney wrote that there are “no major problems with the federal site at this point.” He believes that the switch could be simply done, and then Maryland can use its resources to funnel Marylanders to that site.

“This approach is better for customers,” he wrote, “it doesn’t delay fixing the Maryland Connection, it involves no material technology issues and it is transparent.”

John Wagner contributed to this report.