The controversies engulfing President Trump's White House haven't dented Vice President Pence's popularity on Capitol Hill.

Republican lawmakers, GOP aides and conservative activists have pointed to Pence as the linchpin of the White House's policy operation, even when they've criticized the rest of the administration for its lack of guidance. They say his hands-on approach to building relationships with lawmakers has made him one of the most valuable figures in the Trump administration. "He seems to be constantly taking and hosting meetings in his office in the Capitol with different members," said one House Republican aide.

"It's not unusual to see him walking around, making his way from the House side over to the Senate side for meetings," said another. "He's...willing to do the kind of shuttle diplomacy that it takes to get these things done."

Although the vice president tapped an outside lawyer last week to shepherd his office through the Russia probe, Pence has never been mentioned among the handful of Trump associates who have fallen under the special counsel's scrutiny. That has allowed him to maintain his clout on Capitol Hill, as members need not fear getting dragged into the scandal by association.

Pence has made extensive use of his office on the Senate side of Capitol Hill, where vice presidents have maintained working quarters since the 1800's. But he has also conducted business out of space on the House side of the Capitol, congressional staffers noted. And he has hosted outside conservative groups at the White House for at least one "listening session" designed to collect input on policy proposals.

"He is all class performing his duty as a steward of the president's agenda, not just publicly, but also privately — where it really counts," said David Bozell, president of ForAmerica. Bozell joined Pence at the White House for a healthcare listening session in March.

"What speaks to Pence's clout on Capitol Hill is that Trump's base will take Pence's word over any congressional leader anytime, every time," Bozell added.

Indeed, Pence has emerged as a powerful and credible spokesman for the Trump administration on matters ranging from Obamacare reform to national security.

For example, when tensions with North Korea simmered to a boil in early April, the White House dispatched Pence on a tour of Asian allies to reassure jittery leaders of the U.S.' commitment to their security.

The vice president has traveled the country selling the president's policies to key constituencies — often on weekends, while the president himself spends time golfing at one of his personal properties.

Although Pence has taken on such a public-facing role for the administration, he has remained untainted by the scandals that have ensnared everyone from Attorney General Jeff Sessions to Jared Kushner, Trump's son-in-law and senior adviser. He is so far untouched by the Russia intrigue, for example.

Jason Pye, director of public policy and legislative affairs for FreedomWorks, suggested Pence's experience on Capitol Hill has likely helped him navigate a spate of controversies that have caused trouble for other White House officials.

"Vice President Pence has been at this for a long time, and he's seen controversies come up in the media and go away. He's a pro, and he's focused on the administration's legislative agenda," Pye said. "Honestly, I can't think of someone better to lead this charge on the Hill. He can connect with conservatives in both chambers largely because he has been in their shoes through good times and stressful moments."

Pence spent more than a decade in the House before becoming governor of Indiana in 2013, and many of those in Congress who have sung his praises cite that time as one of the main reasons he has been such an effective legislative liaison.

In addition to his work facilitating discussions among the rank and file, Pence has fostered a particularly close relationship with House and Senate leaders.

A GOP aide said Pence once called House Speaker Paul Ryan's office out of the blue to say he was on his way over, and the two were enjoying a friendly, impromptu lunch within an hour.

Pence has not only hosted congressional leaders for dinner at the vice presidential residence, the aide said, but has also gone a step further by inviting senior members of their staffs to dine in his home on a separate occasion.

The dinners in his residence, which several aides mentioned as proof of Pence's personal touch, have included one evening dedicated solely to members of the Indiana congressional delegation, a Senate aide said. That aide described the Indiana dinner as a "very genuine example of outreach."

"I think he probably feels more comfortable and just is more familiar with working the Hill than a lot of the other folks in the administration," a House aide said. "That's not to criticize other folks in the administration, i just think he was in Congress for so long, and he was even in leadership here, so he just kind of knows the way things work here and he knows the personalities."

Pence chaired the House Republican Conference between 2009 and 2011.

The vice president is expected to figure prominently in Republican discussions about tax reform, which the administration hopes to pass by the end of the year.

His direct involvement in healthcare talks, during which he moderated negotiations between the conservative House Freedom Caucus and the centrist Tuesday Group, helped solidify his image as the White House's congressional ambassador.

At the height of the healthcare battle in the House this spring, a Freedom Caucus aide noted Pence "gave out his direct email to our full group and made clear he has an ‘open door policy' to members of Congress."

The vice president's conservative credentials and work ethic have motivated some conservative leaders to remain dedicated to the Trump agenda, even as the fate of some legislative priorities looks dim amid wavering Republican support. Bozell said Pence has commanded the loyalty of conservative groups like his.

"What's positive about Pence and his team is that the effort is there. He keeps plowing ahead. His team is readily available and committed," he said. "You leave a session with him and/or his team wanting to match their effort."

When dozens of students walked out of a speech Pence delivered to the University of Notre Dame in May, or when he weathered criticism for admitting he avoids dining or drinking alone with women when his wife is absent, Bozell said conservative groups were eager to stand by the vice president.

"ForAmerica, and plenty of others, came to the vice president's defense on the Notre Dame commencement address and when he was attacked on how he lives his personal life," Bozell said. "And all of us would do it again a thousand times over if we had to."