After spending weeks denouncing the mob attack on the Capitol and the past president's role in the assault, Democratic stalwart Christopher S. Murphy of Connecticut will now play a role in handling domestic threats as the new leader of the Senate Appropriations Subcommittee on Homeland Security.

Murphy said the U.S. "faces a significant rise of domestic terrorism." Under his leadership, the homeland security appropriations panel "will play a critical role protecting Americans from domestic extremism," he told CQ Roll Call.

He also pledged to prioritize repairing the U.S. immigration system and boost U.S. cybersecurity protections.

"We also have a lot of work to do to fix our immigration policies in the post-Trump era in addition to shoring up our cyber defense infrastructure, both of which I plan to focus on with my new gavel," Murphy said in a statement.

The junior senator from Connecticut will tackle thorny funding disputes on border resources for Homeland Security, the third-largest government department. In addition to three immigration agencies, DHS also includes the Federal Emergency Management Agency, the Cybersecurity and Infrastructure Security Agency and other agencies. Murphy also noted his panel has "important implications for Connecticut especially as it oversees funding for the Coast Guard."

Murphy also is a member of the Senate Foreign Relations Committee. On the domestic front, however, he is perhaps best known as a proponent for gun control measures following the Sandy Hook school shooting in his home state.

Murphy will be joined on the subcommittee by five other Democrats, including Sen. Jon Tester, D-Mont., the former top Democrat on the panel and now the chairman of the Appropriations Subcommittee on Defense.

Rep. Lucille Roybal-Allard, D-Calif., who chairs the House Homeland Security appropriations panel, said in a statement to CQ Roll Call that it "has been a pleasure" working with Tester previously, and she looks forward to "an equally good working relationship with Sen. Murphy" in his new role.

"We have a lot of work to do together in support of DHS's critical missions and its 240,000 personnel, and we must help repair the damage caused by frequent changes in leadership and the destructive politicization of the department over the last several years," she said.

Among other challenges facing the committees, Murphy and Roybal-Allard will be tasked with handling funding for a politically divisive issue at the center of the last government shutdown: the border wall.

While Murphy has not generally been a major player when it comes to immigration legislation in the Senate, he was a vocal opponent of former President Donald Trump's border wall.

In a February 2020 statement, Murphy slammed Trump's decision to divert funds earmarked for the Department of Defense to finance the wall, accusing him of "playing politics with U.S. national security."

"President Trump just stole money from national security priorities that keep our country safe and National Guard equipment that saves lives in real national emergencies to pay for his ineffective and racist border wall," Murphy said at the time.

Murphy also introduced legislation in 2017 aimed at blocking Trump's travel ban against Muslim-majority nations.

President Joe Biden signed an executive order halting border wall construction, but what will be done with already-constructed barrier, and leftover funds, remain open questions.

Rep. Henry Cuellar, a more moderate Democrat from south Texas who serves as vice chair of the Homeland Security appropriations subcommittee, told CQ Roll Call in an interview Tuesday that he hopes to return funds meant for the military. He also wants to redirect appropriated Homeland Security funds from wall construction to technology at the border, both for immigration surveillance along the border and to facilitate trade at entry ports.

"There are folks that don't want to see any technology, don't want to see any extra personnel, no more Border Patrol, nothing to help border Patrol and ICE. And of course, on the other side, you got Republicans who want wall, wall, wall, wall. So there are two different positions here," Cuellar said.

As chairman, Murphy will be working closely with Sen. Shelley Moore Capito of West Virginia, the former subcommittee chair who now becomes the panel's top Republican.

In a statement, Capito said that the subcommittee will continue to tackle issues involving the "southern border, evolving cybersecurity threats, natural disasters, and the ongoing COVID-19 pandemic."

"For the past couple of years it was my honor to serve as chairman of this subcommittee and now as ranking member, I will be able to continue to address the needs of West Virginians and all Americans when making these key funding decisions," she said.