The Supreme Court has handed President Biden loss after loss in a series of tense legal battles. His most recent defeat — a COVID-19 vaccination mandate that would affect a sweeping number of employers — may be the most painful yet for the administration.

The Supreme Court on Thursday blocked enforcement of the Occupational Safety and Health Administration's (OSHA) vaccination mandate for businesses with 100 or more employees. The OSHA mandate was a signature COVID-19 policy Biden had been pushing for months despite protests from conservatives.

SUPREME COURT HANDS BIDEN COVID VAX MANDATE DEFEAT, SPARKING FURY FROM LIBERALS

The court came within one vote of sweeping the mandate completely, but conservative Chief Justice Roberts and Justice Kavanaugh sided with their liberal colleagues and allowed the health care worker mandate to go into effect.

FILE PHOTO: U.S. President Joe Biden delivers remarks on the administration's coronavirus disease (COVID-19) surge response in the South Court Auditorium at the White House in Washington, U.S., January 13, 2022. REUTERS/Kevin Lamarque/File Photo

President Biden delivers remarks on his administration's coronavirus surge response in the South Court Auditorium at the White House in Washington Jan. 13, 2022. (REUTERS/Kevin Lamarque/File Photo)

But the failure to secure his often touted employer vaccine mandate was only the latest defeat Biden has suffered at the highest court.

The Supreme Court voted in a 6-3 ruling to overturn Biden's eviction moratorium in August 2021, with the court's three liberal-leaning justices dissenting.

The Biden administration previously admitted that it lacked the legal authority to extend the federal moratorium after it expired in July 2021. The Centers for Disease Control and Prevention (CDC), however, issued a new moratorium that was set to expire in October.

White House press secretary Jen Psaki said in August that Biden would have "strongly supported" a decision by the CDC to further extend its eviction moratorium but noted that the Supreme Court declared in June that the CDC could not grant such an extension without congressional approval. The White House said Biden’s idea for a new, 30-day eviction moratorium focusing on counties with high infection rates was also shot down by the CDC.

This artist sketch depicts Mississippi Solicitor General Scott Stewart, standing while speaking to the Supreme Court, Wednesday, Dec. 1, 2021, in Washington. Center for Reproductive Rights Litigation Director Julie Rikelman is seated right. Justices seated from left are Associate Justice Brett Kavanaugh, Associate Justice Elena Kagan, Associate Justice Samuel Alito, Associate Justice Clarence Thomas, Chief Justice John Roberts, Associate Justice Stephen Breyer, Associate Justice Sonia Sotomayor, Associate Justice Neil Gorsuch and Associate Justice Amy Coney Barrett. (Dana Verkouteren via AP)

This artist sketch depicts Mississippi Solicitor General Scott Stewart standing while speaking to the Supreme Court, Wednesday, Dec. 1, 2021, in Washington, D.C. (Dana Verkouteren via AP)

In the same month, the Supreme Court ruled that the Biden administration's attempt to get rid of the Trump-era "Remain in Mexico" policy violated federal law. 

Established by the Trump administration in January 2019, the "Remain in Mexico" policy, or Migrant Protection Protocols (MPP), returned migrants to Mexico to await asylum hearings instead of keeping them in the United States. The Trump administration presented the policy at the time as an important part of its efforts to end "catch-and-release" and stem the flow of illegal immigration. Critics of the policy claim the policy was cruel and put migrants at risk of violence and exploitation in Mexico.

CLICK HERE TO GET THE FOX NEWS APP

Biden campaigned against the MPP and tried to get rid of it following his inauguration, but his attempts were blocked by federal appeals courts after Texas and Missouri sued.

Alejandro Mayorkas

Secretary of Homeland Security Alejandro Mayorkas speaks during a news conference at The National Press Club in Washington Sept. 9, 2021. (AP Photo/Jose Luis Magana)

The Biden administration asked the Supreme Court in December if it was required to continue the Trump-era policy. In the meantime, the administration is planning to restart the Trump-era policy after its losses in the lower courts.

Fox News's Houston Keene, Jon Brown and The Associated Press contributed to this report.