President Trump's approach to filling the judiciary won praise from conservatives in the immediate aftermath of Justice Neil Gorsuch's confirmation, but Republicans' inaction on lower court nominees has begun to rub conservative legal experts the wrong way.

Some conservatives say the confirmation process for lower court nominees is moving much too slow. A source familiar with the judicial selection process who advises the White House said Trump has signed off on "dozens" of nominees to the lower courts but has not sent them over to the Senate, where the lack of action on pending nominees has become a problem.

"You don't want to be in a situation where the White House is rolling out nominee after nominee and they're just sitting there in dead air, in dead space," the source said. "So at the end of the day, if you want to speed up the pace with which the president puts out nominations, the other thing you have to do is you have to have a Senate Judiciary Committee that's actually going to move these people through because there's not a lot of value to naming people and then having them sit for months."

The source said the White House has moved "relatively quickly as compared with the last Republican administration" on advancing prospective nominees, which is the result of a "very intense process." The source said the judiciary committee's pace of considering judicial nominees has been "pretty abysmal" thus far. As the committee moves more quickly, the source adds, the president would begin naming clusters of new nominees on a rolling basis, week after week.

A Senate Judiciary Committee representative said the committee is processing the nominations as it receives them and highlighted Trump's role in the process.

"Judicial nominations are the president's to make," the spokesman said in a statement. "The president recently announced his first nominations and the committee is processing them as soon as is possible once all of the required paperwork is finally submitted. The Judiciary Committee will continue to consider nominations as the president makes them."

John Malcolm, Heritage Foundation's legal director who helped craft Trump's Supreme Court short lists and has made recommendations for some lower court positions, said he is dissatisfied with the judicial confirmation process, too.

"I think the whole confirmation process for all of these positions and throughout the executive branch and the judicial branch has been going at a disappointingly slow pace," Malcolm said. "I recognize, of course, that Neil Gorsuch took up a lot of time and attention and maybe sucked some of the oxygen out of the room, but, look, there's only been one other nominee who's gone through the Senate Judiciary Committee that's a nominee to the federal bench."

He added about the pace of the judicial selection process, "From a conservative standpoint, there may be good, sufficient, and understandable reasons for it, but it's frustrating nonetheless."

More than 100 vacancies exist on lower courts for Trump appointees to fill, and his first federal appeals court nominee, Judge Amul Thapar, was confirmed by the Senate to the 6th Circuit Court of Appeals last week. Pending nominees have faced hostile scrutiny from liberals while they wait for Senate Republicans to take action on their nominations.

John K. Bush, who the White House named as a nominee to the 6th Circuit Court of Appeals on May 8, came under fire from the Alliance for Justice this week. The liberal legal group argued that Bush's political commentary written under a pseudonym online should " disqualify" him from serving on the federal bench. Legal professionals spanning the political spectrum subsequently offered defenses of Bush. Similar attacks on other pending Trump nominees awaiting hearings loom, as the Alliance for Justice told the Washington Examiner it will have similar "serious reservations" about the president's other picks.

Whether Trump's nominees wilt under liberal pressure remains to be seen. But conservative legal scholars have begun openly discussing the possibility that Senate Republicans should scrap or modify the "blue slip" tradition to bypass expected Democratic obstruction and confirm Trump nominees. Under the Senate's blue slip procedure, a state's senators are consulted by the White House before a president nominates a judge from that state, regardless of party affiliation, explains a Congressional Research Service report detailing the blue slip policy. The home-state senators then have the opportunity to block a nominee from getting a Senate Judiciary Committee hearing and vote.

Senate Republicans, who moved earlier this year to kill the filibuster of Supreme Court nominations, soon may decide to change the blue slip tradition with the approval of conservatives. Malcolm said he thinks "de-emphasizing" the blue slip process, not necessarily eliminating it altogether, makes sense for appellate court slots "since appellate court nominees by definition cover several states, not just the state from which they come from."

"The blue-slip process is not a Senate rule, it's not written in stone anywhere," Malcolm said. "I certainly do think that modifying, at the very least, the blue-slip process with respect to appellate nominees makes some sense. But that's an internal, informal rule, and unlike the filibuster, it is certainly one that has been used to great advantage often by both sides."

Malcolm's comments echo remarks made by Leonard Leo, an adviser to Trump on the Supreme Court and judiciary, earlier this month. Leo said "the blue slip has never been holy writ" in comments about how to overhaul the judiciary at the Acton Institute.

Malcolm and Leo, who took a temporary leave from his position as executive vice president of the Federalist Society when helping to confirm Gorsuch, played large roles in developing Trump's Supreme Court short lists. Their public skepticism of the blue slip procedure could portend poorly for its future if Senate Republicans adopt their perspective.