Washington (CNN) A newly released draft memo by officials in the departments of Homeland Security and Justice reveals how far the Trump administration was willing to go to deter migrants, many of whom are seeking asylum, from approaching the US-Mexico border.

The draft memo , dated December 2017, was obtained by Sen. Jeff Merkley, D-Oregon. It not only provides a snapshot of the administration's plans to roll out policies aimed at dissuading migrants from trekking north but also shows how early on those options were being discussed.

Merkley told CNN the memo was obtained via a government whistleblower.

The draft, called "Policy Options to Respond to Border Surge of Illegal Immigration," was put together at a time when border apprehensions had dropped compared to the previous year. In December 2017, 40,519 people were apprehended at the border, roughly 18,000 fewer than December 2016, according to Customs and Border Protection data.

Below is a breakdown of some of the options floated in the draft memo that eventually took effect.

Prosecuting migrant parents

This is listed under a section titled "short term (next 30 days) options." And as became evident months later, it came to fruition.

In April 2018, then-Attorney General Jeff Sessions announced the "zero-tolerance" policy that led to families being separated, given that children cannot be kept in federal jail with their parents. The policy sparked outrage across the country and was later reversed in a June executive order.

The draft memo makes clear that the administration was aware of the attention the policy might bring. And that was the point.

"The increase in prosecutions would be reported by the media and it would have substantial deterrent effect," the memo states.

Separating families

The title, "Separate Family Units," and explanation of this section are significant. It explicitly states what the administration had long denied. After the rollout of the "zero-tolerance" policy, the administration repeatedly said that there was no intention to separate families. In June 2018, DHS Secretary Kirstjen Nielsen said on Twitter , "We do not have a policy of separating families at the border. Period." But the draft memo demonstrates that that was not the case.

The draft explains that children would be placed in the custody of Health and Human Services as unaccompanied children, which ultimately led to a slew of issues when trying to reunify families. A new inspector general report released Thursday laid out how the lack of documentation and tracking of children created a number of challenges for HHS. The report found that "thousands" more children were separated from a parent or guardian last year than was previously reported.

While not acted upon, comments in the margins also suggest denying children asylum hearings. "If CBP issues an ER [expedited removal] for the entire family unit, places the parents in the custody of the U.S. Marshal, and then places the minors with HHS, it would seem that DHS could work with HHS to actually repatriate the minors then," the comment reads.

"It would take coordination with the home countries, of course, but that doesn't seem like too much of a cost to pay compared to the status quo."

Background check of sponsors

Last year, the administration rolled out a controversial policy that required that adult members of a sponsor's household to submit fingerprints to the FBI when applying to take in a child. Immigrant advocates argued that the policy led to children remaining in shelters for longer periods of time because sponsors -- some of whom live in mixed-status households -- were afraid to come forward.

The administration, as shown in the draft, was aware of the possible repercussions.

"There would be a short term impact on HHS where sponsors may not take custody of their children in HHS facilities, requiring HHS to keep the UAC's in custody longer," it reads, under a section titled, "near term (2-6 months) options." The policy was reversed in December.

Last year, the Trump administration erected a temporary tent facility in Tornillo, Texas, to hold children who had arrived unaccompanied at the southwest border or been detained as a result of the administration's "zero-tolerance" policy.

The facility came under scrutiny last November when the HHS Inspector General Daniel Levinson warned of "significant vulnerabilities," including not properly vetting staff and a "dangerously low number of clinicians."

It's expected to shut down before the end of the month.

Responding to the release of the memo Thursday, DHS spokeswoman Katie Waldman said, "The Trump administration has made clear that all legal options are on the table to enforce the rule of law, rein in mass unchecked illegal immigration, and defend our borders."