Though President Donald Trump has seen a number of his key personnel picks secure Senate confirmation in recent days, there is one critical nomination that continues to hang in the balance.

As The Hill reports, Trump's choice to become director of national intelligence, former Congresswoman Tulsi Gabbard, is contending with doubts raised by a handful of key Republican lawmakers after what some suggest was a bumpy confirmation hearing last week.

Hearing causes concern

Gabbard's Thursday hearing before the Senate Intelligence Committee is said to have left certain GOP legislators with lingering concerns about her suitability for the influential administration role.

Of particular worry to some were Gabbard's answers regarding whistleblower Edward Snowden, her past interactions with foreign leaders, and her take on the appropriate scope and role of government surveillance.

One person familiar with the current state of the process told NBC News, “It's 50-50 she gets through.”

Though no Republican in the Senate has yet come out and declared their opposition to Gabbard's nomination, some observers suggest that the White House may be contemplating the same sort of pressure campaign used to shepherd Defense Secretary Pete Hegseth's confirmation process to success depite the controversies that he brought to the table.

Even so, an aide to Senate GOP leadership told The Hill that confidence about Gabbard's prospects is still there, saying, “There's no need for a plan B because plan A is going to work. No senators said they're no or announced they're opposing her. And those who have expressed further questions are getting answers.”

Doubts, questions persist

The type of doubts that may remain in the minds of some GOP lawmakers have been articulated in recent days by the likes of Democrat Sen. Mark Kelly (AZ), who believes that Gabbard's hearing contained some unwelcome answers for those who may have been on the fence.

“I think there's a lot of questions still that my Republican colleagues have. I think some of them have been answered, and probably in a way that she was hoping would have gone the other way,” Kelly said.

Indiana Republican Sen. Todd Young is reportedly among those who are wavering when it comes to Gabbard's confirmation, saying that her responses to questions about Snowden were “notable” and not necessarily in a good way.

“When we find Americans, whether private citizens or contractors or uniformed personnel, have shared sensitive designs about military technology or plans to a foreign government...we rightfully throw the book at them. Snowden did just that. Yet you have argued many times that he should be pardoned,” Young said to Gabbard during the hearing.

Political commentator Eric Daugherty reported on Sunday that Young is leaning toward a no vote on Gabbard, putting her chances of confirmation in further doubt, given the absence of firm commitments of support from a number of other key Republicans.

Promising signs emerge

Despite the concerns that remain about Gabbard's hopes of confirmation, Sen. Susan Collins (R-ME), a frequent critic of Trump picks, offered some encouraging -- yet still noncommittal -- words, saying, “I was happy with her responses to my questions, including the question of whether she would recommend a pardon of Edward Snowden, where she clearly said no.”

Sen. Lindsey Graham (R-SC), whose support was the subject of speculation in recent weeks, said on Sunday that he is a “yes” on Gabbard, but whether she will ultimately secure the full measure of support needed is something that remains to be seen.