The court currently has a 6-3 conservative supermajority, but both Barrett and Roberts have at times broken ranks and voted with the court's liberal wing in rulings that have infuriated the MAGA base.
The high court handed the U.S. president a significant setback when it ruled Wednesday that the Trump administration must abide by a lower court order to unfreeze $2 billion in foreign aid.
The aid was blocked after Trump signed an executive action his first day in office ordering the funding freeze while his administration scoured U.S. spending for what Trump and his allies characterize as "waste, fraud and abuse."
A lower court judge subsequently ordered the administration to unblock the aid in response to a lawsuit filed by nonprofit organizations in connection to the Trump administration's freezing of foreign assistance through the U.S. Agency for International Development (USAID) and the State Department.
In a 5-4 ruling on Wednesday, Barrett and Roberts joined Justices Sonia Sotomayor, Elena Kagan and Ketanji Brown Jackson and left in place the ruling by U.S. District Judge Amir Ali.
Mike Cernovich, a longtime conservative activist and Trump supporter, amplified a video of Barrett and Trump interacting during his address to a joint session of Congress.
"She is evil, chosen solely because she checked identity politics boxes," Cernovich wrote. "Another DEI hire. It always ends badly."
Mike Davis, a former law clerk for Gorsuch and the former chief nominations counsel for Republican Senator Chuck Grassley, didn't name Barrett directly but echoed Cernovich's criticisms of diversity, equity and inclusion (DEI) initiatives, which Trump has dismantled across the federal government.
He wrote on X: "President Trump will pick even more bold and fearless judges in his second term. Extreme vetting. No DEI. No missteps."