President Biden has used his first term in office to end many of the border and immigration policies of former President Donald Trump's administration, actions some experts argue have led to the ongoing crisis at the southern border.

"By ending Remain in Mexico, encouraging asylum fraud, and mass paroling illegal aliens, Biden has provided entry to millions of inadmissible aliens," Lora Ries, the Director of the Heritage Foundation's Border Security and Immigration Center, told Fox News Digital. "By mass releasing them instead of following the mandatory detention statutes, Biden has allowed the millions to remain in the U.S. longer, knowing it is much harder to deport those who are not in detention."

Ries' comments come amid an ongoing crisis at the U.S. border with Mexico that shows no signs of slowing, with the latest U.S. Customs and Border Protection data showing Border Patrol encounters with migrants once again reached an all-time high towards the end of 2023, peaking at just over 300,000 in December.

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The continued crisis promises to garner the attention of voters ahead of the 2024 Presidential Election, with voters giving the president low marks on his handling of immigration. According to a new Monmouth University poll released last week, just 26% of Americans indicated they approve of Biden's handling of immigration. Those numbers are worse among political independents, with only 21% of the crucial demographic signaling support for how the president has handled the issue.

Ries believes that much of Biden's unpopularity with immigration policy can be traced back to decisions to reverse the policies of Trump, the GOP frontrunner who is seemingly poised for a 2024 rematch with the president.

"By every measure, Biden took a secure border and intentionally unsecured it," Ries said. "His policies have resulted in historic numbers of: inadmissible alien encounters and releases, terror watchlist hits, unaccompanied alien children, migrant deaths, border search and rescues, and American drug deaths, largely from fentanyl coming from Mexico."

Like Ries, House Speaker Mike Johnson has been a vocal critic of Biden's immigration policies, saying in a January release that the president has "worked to systematically undermine America’s border security."

The release detailed 64 Biden administration policies or actions that Johnson argued helped to exacerbate the border crisis, 16 of which were reversals of Trump-era policies. Some of those actions were taken on Biden's first day in office, including the termination of the National Emergency at the Southwest border (Proclamation 9844), which ended emergency construction of the border wall.

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Mark Morgan, a visiting fellow at the Heritage Foundation's Border Security and Immigration Center, told Fox News Digital that the sheer volume of Biden's executive actions on the border have led to negative consequences.

"The magnitude of what he did created chaos at the border," Morgan said.

But Morgan also pointed to specific Trump-era policies that Biden changed, including ending the Asylum Cooperative Agreements, known as the ACA. 

Morgan argued that the ACA "mirrored the international standard," which was to encourage individuals making asylum claims to seek protection in the first safe country they are able to arrive in.

"We should encourage everyone to seek relief in that first safer country rather than coordinate with the cartels and risk your life and your safety and your finances to then forum shop and try to get to the United States," Morgan said.

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By eliminating that policy, Morgan argued that it encouraged migrants who are actually moving for economic motivations to seek asylum in the U.S., adding significant strain to American border security.

"It deterred those individuals from risking their life and their financial well-being because they knew they were not going to be released in the United States," Morgan said.

The second administration policy decision Morgan pointed to was Biden's decision to end the Migrant Protection Protocol, more well known as the "Remain in Mexico" policy.

Morgan argued that the goal of many migrants who come to the border and claim asylum is to be released into the U.S., something that did not happen under the Remain in Mexico policy. Instead, asylum seekers were forced to wait on the other side of the border while their claim was processed, eliminating part of the incentive for those migrants who seek to abuse the asylum process and gain entry into the United States.

"The Remain in Mexico program didn't deny anybody asylum," Morgan said. "They simply said that you're going to wait in Mexico while you're going through asylum. We're not going to release you in the United States to never be heard from again."

Ries shared similar sentiment, arguing that reinstating both of those policies would go a long way to help alleviate the current crisis.

"Preventing asylum fraud includes requiring aliens to apply for protection in the first safe country in which they enter, not country shop to come to the U.S., and returning them to that first safe country," Ries said. "It also includes fully implementing Remain in Mexico (and Canada), while getting back to the traditional U.S. Refugee Admissions process, where foreigners apply for refugee protection overseas, providing adjudicators better proximity to applicants’ documents and histories, and more time to thoroughly investigate and vet applicants."

Instead, Ries argued that the Biden administration's policies have resulted in severe consequences.

"America has open borders and has lost its sovereignty. We face serious national security threats, particularly from the 1.8 million known gotaways who evaded the Border Patrol during this Administration," Ries said. "Americans have lost precious lives and public safety from the cartels, gangs, criminals, and drugs that have crossed the border."

The White House did not immediately respond to a Fox News Digital request for comment.