The US has yet to fill the role of National Cyber Director in the four months since Chris Inglis resigned, and it’s worrying some lawmakers.

According to Axios, Sen. Angus King (I-Maine) and Rep. Mike Gallagher (R-Wis.) sent a letter to President Biden questioning why Inglis’ replacement had not been selected, and urging the President to nominate acting director Kemba Walden.

Despite the letter, the White House has been noticeably silent on the issue.

“I’m really puzzled; I just don’t know what’s going on,” King told Axios. “This is an important job, and it’s an important moment and they have a highly qualified, able acting director.”

It’s unusual for such an important role to go unfilled, especially when there’s bipartisan support for an existing candidate. The silence is especially telling given how much emphasis the Biden administration has placed on cybersecurity.

Sen. King believes the silence may speak to internal pressure or objections that may be in play.

“The lack of an appointment itself indicates that there’s some reluctance, when there’s an obvious nominee waiting in the wing,” King said. “I’m not going to speculate on what the cause is, but all I’m going to say is that it’s a dangerous lapse, and it’s resolvable.”