A planned Senate Judiciary Committee vote on William P. Barr’s nomination to serve as attorney general has been delayed for a week, as Democrats continue to raise concerns about whether he will allow special counsel Robert S. Mueller III to finish his probe and publicize the results unimpeded.

The delay, which is customary for high-profile nominations, is not expected to impede Barr’s eventual chances of being confirmed by the full Senate. But it is the latest reflection of the deep partisan tension surrounding Barr’s nomination, most of which centers on Democrats’ desire to protect Mueller’s probe from being unduly constrained.

The committee postponed its vote on Barr as one of over 40 nominations the panel was scheduled to vote on Tuesday, but decided to delay until its next meeting.

In both his public testimony and his written answers to senators’ questions, Barr has repeatedly refused to give senators any firm guarantee that he will release Mueller’s report to Congress and the public free of redactions. In similar fashion, he has only promised to ask for, but not necessarily heed, the advice of the Justice Department’s ethics counsel on the matter of whether he should recuse himself from oversight of the probe.

That has particularly frustrated Democrats, who take issue with a memo Barr penned last year arguing that in scrutinizing the actions of the Trump campaign, Mueller appeared to be interpreting an obstruction of justice statute too broadly. Democrats fear the memo is evidence Barr, who served as attorney general under President George H.W. Bush during the early 1990s, might seek to constrain the scope of Mueller’s probe.

Though Barr has said that, as a former attorney general, he often weighs in on topics of the day, he acknowledged in written answers to lawmakers that he could not recall another case in which he sent the Justice Department such a memo.

As he looks to return to his previous post leading the Justice Department, Barr has met privately with more Senate Republicans than Democrats. Still, it is unclear if he could change Democrats’ minds in additional meetings, as the Democrats who have met with him behind closed doors have emerged saying they were still unsatisfied with Barr’s answers concerning Mueller.

But Barr doesn’t need any Democratic support to be confirmed. Under rules changes that the Democratic-led Senate adopted in 2013, only a simple majority of senators’ votes are needed to confirm a Cabinet nominee.

Yet the delayed Judiciary committee vote means that it will be difficult for the Senate to confirm Barr before current acting attorney general Matthew G. Whitaker is due on Capitol Hill on Feb. 8 to answer the House Judiciary Committee’s questions about his oversight of the Mueller probe.