President Donald Trump’s surprise decision to name Army Lt. Gen. H.R. McMaster as his new national security advisor (replacing Michael Flynn, who served just 24 days in that role) has garnered rare praise from the across the political and policy spectrum. Yet while Trump has drawn criticism for appointing so many retired generals to his administration, McMaster is the first senior official who will serve as a Trump political appointee while remaining on active duty. This anomaly presents some unique challenges to both McMaster and those who will interact with him in what is indisputably one of the most powerful and influential positions in the U.S. government.

McMaster is the third active-duty officer to serve as the national security advisor. The previous two were both appointed by President Ronald Reagan: Vice Admiral John Poindexter, who held the position from 1985 to 1986, and then-Lt. Gen. Colin Powell from 1987 to 1989. Other active-duty generals have held lesser staff roles on the National Security Council: Alexander Haig and Brent Scowcroft both served as the deputy national security advisor while still in uniform, from 1970 to 1973 and 1973 to 1975, respectively. More recently, Lt. Gen. Douglas Lute served as deputy national security advisor for Iraq and Afghanistan from 2007 to 2013, retiring from active duty in 2010 but remaining in that position. Nonetheless, such active-duty postings remain rare, largely because they put senior uniformed officers right in the middle of a highly political White House staff.

McMaster’s unexpected appointment has spawned a lot of discussion about what it will mean to have an active-duty general serve as the national security advisor, especially in today’s hyper-partisan environment. His appointment has surfaced a number of myths and understandable concerns – but, in this case at least, perhaps also a bit of unexpected promise.

Myth #1: McMaster will not need Senate confirmation. It is true that McMaster does not need Senate confirmation to be the national security advisor. But he does need Senate confirmation to serve in that position as an active-duty three-star general. All three- and four-star ranks are temporary and linked to specific positions. Officers nominated to a position at either rank must be confirmed by the Senate – and must be reconfirmed if they switch positions. If that does not happen within 60 days, they automatically revert to two-star rank. For those of you who are eagerly awaiting a confirmation hearing, though, don’t turn on C-SPAN just yet: The Senate rarely holds them for three-star officers, and usually just votes after an updated background check is complete. That’s what happened with Colin Powell in 1987, and will almost certainly be the case for McMaster since he doesn’t face any serious Senate opposition. Of course, the president could always avoid this requirement entirely by asking McMaster to retire, but so far Trump seems committed to keeping McMaster on active duty.

Myth #2: A 3-star in the White House can’t tell the 4-stars in the Pentagon what to do. Until last week, McMaster was outranked by the Secretary of Defense, almost all Senate-confirmed Pentagon appointees, and every four-star general and admiral in the U.S. military. No longer. As the national security advisor, his military rank effectively comes off. He reports directly to the president, just like the other senior-most White House advisors and the cabinet secretaries. He’s not in the military chain of command, so he cannot issue military orders. But he can issue policy directives – in the name of the president – throughout the executive branch, including to generals and admirals. (Interesting tidbit: according to the official Order of Precedence, which establishes the protocol order for all U.S. government officials, the national security advisor ranks significantly higher than the chairman of the joint chiefs of staff, the service secretaries, and the service chiefs. Then again, so do the deputy administrator of the Small Business Administration and the head of the Nuclear Regulatory Commission.)

Myth #3: McMaster, Secretary of Defense Jim Mattis and Secretary of Homeland Security John Kelly will act as a unified bloc. Some believe that the three combat-seasoned U.S. generals sitting atop the national security apparatus will routinely act as a unified alliance and dominate the president’s national security advice. But while all three have shared battlefield backgrounds, each now has very different portfolios and constituencies. In particular, McMaster’s primary responsibility is to ensure that the president gets access to all viewpoints and possible options without putting his thumb on the scales. The national security advisor’s views and preferences may become decisive at the end of a debate, but he must first gather all the viewpoints, get them aired in principals’ meetings, and ensure all options are considered by the president. That said, these three generals do share many similar views that fall squarely within the traditionalist camp of the administration. Whenever their views do align, they will present a very powerful argument within an administration largely bereft of real-world national security experience at the senior level.

Concern #1: An active-duty national security advisor will not be able to oppose the president because he is the commander in chief. The president remains at the top of the military chain of command, normally many echelons above the level of a three-star general. The president also has the authority to issue directives to any member of the military or the executive branch. But in practical terms, this authority carries little weight inside White House deliberations. McMaster has an overarching duty to make his considered opinions known and to push back against the president in order to make sure that he makes fully informed decisions. Early signs suggest this won’t be a problem for McMaster. He reportedly told the National Security Council staff on Friday that the term “radical Islamic terrorism” was unhelpful because terrorists are “unIslamic” – thus rejecting a term Trump used repeatedly throughout the campaign and in his first weeks in office.

Concern #2: An active-duty national security advisor will only exacerbate the hammer and nail problem. Since McMaster has replaced Flynn, a retired three-star general, the total number of generals in senior administration positions will not change – but that number nevertheless remains unprecedented. That tally has led to renewed fears about the ever-increasing militarization of U.S. national security and foreign policies. Even President Obama warned about the dangers of this trend in his 2014 commencement speech at West Point: “U.S. military action cannot be the only – or even primary – component of our leadership in every instance. Just because we have the best hammer does not mean that every problem is a nail.”

This is a legitimate concern. Given the number of military men in the administration’s senior ranks, McMaster will have to work hard to ensure non-military perspectives and courses of action get a full and fair hearing in National Security Council deliberations. However, McMaster is probably better positioned to do this than almost any other active or retired general because of the unusual breadth and scope of his background (more on this below). And contrary to the conventional wisdom, senior military officers do not always support aggressive military options. Work by Peter Feaver and Christopher Gelpi has shown that civilian elites are more supportive of using military force, and for a broader range of scenarios, than military elites. It makes sense that those who have directly experienced the costs and chaos of war – a category that includes pretty much everyone who has served in uniform since 2001 – are often far more cautious about the use of military force than those with little, if any, experience. To the uninitiated, U.S. military power can seemingly offer an option that is quick, decisive and, at times, nearly bloodless. Those who have seen the results of death, dismemberment, and destruction up close can offer a sobering reality check to unbridled enthusiasm for using military power.

Concern #3: An active-duty national security advisor will be too concerned about his future military career. Shortly after stepping down as Reagan’s national security advisor, Powell was promoted from three-star to four-star general and was later selected by President George H.W. Bush to be the chairman of the joint chiefs of staff. Haig served as the national security advisor as a two-star general, but when he left that position President Nixon promoted him to four-star rank – skipping three-star rank entirely – and named him Army vice chief of staff. Some people with whom we’ve spoken have expressed concern that McMaster’s advice to the president may somehow be colored by his future ambitions. While there is no way to decisively dispel this worry, McMaster’s career certainly suggests he is an inordinately independent-minded leader who has always shown an iconoclast’s utter disregard for ascending the promotion ladder. As many recent reports have noted, his outspokenness and independence as a younger officer meant that he was twice rejected for promotion to one-star general, and probably would have been rejected on his third and final try had Secretary of the Army Pete Geren not intervened by putting Gen. David Petraeus in charge of that promotion board. When TIME magazine named McMaster as one of The 100 Most Influential People of 2014, one of your loyal “Strategic Outpost” columnists described him as having “repeatedly bucked the system and survived to join its senior ranks.” Bottom line: McMaster seems a very unlikely sycophant.

Concern #4: An active-duty national security advisor will not have enough Washington experience to successfully navigate the intricacies of the West Wing. This could be a problem for many active-duty officers, but not for McMaster. A regular speaker for years at Washington think tanks and well-known among the policy establishment and on Capitol Hill, he is not simply a muddy-boots soldier thrust into the byzantine world of national politics. Frequently described as a warrior scholar, he not only knows many of the key Washington players but has also spent a great deal of time studying, thinking, and writing about both the use of force and the policy-making process. Most notable – and eerily prescient given his new job – was his PhD dissertation turned into best-selling book Dereliction of Duty, which indicted the Vietnam-era joint chiefs for failing to confront President Lyndon Johnson over the foundering war in Indochina. McMaster also dissects the myriad problems of Johnson’s National Security Council at the time, an analytic experience that may prove quite helpful in charting the right path in his new role.

The president’s decision to have McMaster remain on active duty is, as we noted, not without precedent, but it brings unique challenges. Fortunately, Trump’s choice for this immensely influential position is up to the task. H.R. McMaster will need to muster every ounce of his exceptional mix of battlefield experience, bureaucratic understanding, and interpersonal charisma to be effective in his new job. We should all be cheering loudly for that outcome.

Lt. Gen. David W. Barno, USA (Ret.) is a Distinguished Practitioner in Residence, and Dr. Nora Bensahel is a Distinguished Scholar in Residence, at the School of International Service at American University. Both also serve as Nonresident Senior Fellows at the Atlantic Council. Their column appears in War on the Rocks every third Tuesday. To sign up for Barno and Bensahel’s Strategic Outpost newsletter, where you can track their articles as well as their public events, click here.