WASHINGTON — Colin Kahl, the Biden administration’s nominee to be undersecretary of defense for policy, faced tough questioning at a Thursday hearing in front of the Senate Armed Services Committee. But while questions about partisanship and past tweets dominated the event, there were still some inquiries that give insight into how Kahl will approach his job if confirmed.

The USD-P role is often described as the third-most powerful civilian job in the department, with a wide-ranging portfolio. Among the responsibilities: formulating policy for homeland defense, nonproliferation and arms control, and regional policies for areas covered by the combatant commands; reviewing war plans; regularly attending interagency meetings as the top representative from the Department of Defense; and handling bilateral relationships with allies.

Here were some highlights from Kahl’s appearance before the committee:

Iran: Kahl is known as having a major part in the creation of the 2015 Joint Comprehensive Plan of Action, most commonly known as the Iran nuclear deal. During the Trump administration, he continued to defend the agreement in public comments. So it is no surprise that a significant amount of time was taken up to discuss the agreement, which was and remains a major target for Republican members of Congress.

Kahl continued to defend the deal, saying that the decision by the Trump administration to leave the agreement sped up the “breakout time” needed by Iran to achieve a nuclear weapon. However, he stressed that does not mean working toward a new nuclear agreement precludes the U.S. from taking aggressive action, whether by additional sanctions or military strikes against Iranian-backed militias if needed.

“It’s absolutely essential we prevent Iran from ever acquiring a nuclear weapon. It’s also essential we prioritize the protection of our forces” even while pursuing diplomatic efforts, he said. “We have to remain vigilant against the other threats Iran poses.”

Nuclear weapons: Aside from Iran, the biggest policy question facing Kahl came from multiple Republican members trying to lock him down in support of nuclear modernization — specifically the Ground Based Strategic Deterrent program, which is set to replace the Minuteman III intercontinental ballistic missile.

The future of the GBSD is developing into a major target of progressive Democrats, who argue the Minuteman III could receive a life extension instead of replaced with a new program, which is expected to cost more than $260 billion over the life of the weapon.

Kahl broadly showed support for the nuclear triad, saying there is “nothing more important to our national survival” and that “the triad has been a bedrock of deterrence and stability for many decades, and my personal position is that the triad remains a critical hedge against the possibility of technological modernization by our adversaries.”

However, when asked about specific programs like the GBSD or a new nuclear cruise missile, Kahl was more cautious, saying that while he has no reason to doubt public statements from U.S. Strategic Command that GBSD is necessary, he wants to see the classified information about the program before weighing in.

While that line echoed statements from Defense Secretary Lloyd Austin and Deputy Defense Secretary Kathleen Hicks, who both were careful not to endorse the GBSD program wholeheartedly, it drew ire from several senators, including ranking member Sen. Jim Inhofe, R-Okla., who gave extra time at the end of the hearing for Sen. Tom Cotton, R-Ark., to press the GBSD issue.

While Cotton, who has said he will vote against Kahl, pushed the nominee on the GBSD issue, Kahl denied he was being “evasive.”

He explained that he has been out of government for four years and doesn’t have access to classified information. “So it’s something I’ll have to get a classified assessment on including the capabilities, the costs and the life-extension program.”

Kahl also twice during the hearing said he does not believe a “no first use” nuclear weapons policy makes sense for America.

National Defense Strategy: The USD-P is the lead official for the creation of the NDS. Kahl called the 2018 version “excellent,” particularly for its focus on great power competition with China and Russia, but added that tweaks are likely needed.

The DoD “should consider geo-political shifts, intensifying competition with China, transnational threats (including climate change and COVID-19 and other biological threats), and the evolving technology landscape in its review and development of the next NDS,” Kahl wrote.

He also noted that the 2018 document assumed “sustained defense budget growth and anticipated a rebalancing of U.S. commitments from the Middle East to the Indo-Pacific region, though neither has fully materialized,” a sign that hard choices within the department may be part of the NDS process.

Asked to rank the greatest regional areas of focus for the department, Kahl said the Asia-Pacific is “No. 1 with a bullet,” followed by Europe and the Western Hemisphere, before noting “we need to right-size our presence in the Middle East and Central Asia.”

He also said the document should address the effect climate change might have on operations, energy resilience and DoD installations.

Climate change: Speaking of which, Kahl said that for the department, “climate change is going to change everything” and will be a major priority going forward — something already outlined by Austin in a late January memo.

“It will change the operational environment for the military in strategically vital areas like the Arctic. It’ll create new contingencies for humanitarian emergencies and violent conflict that the department may be called upon to respond to,” Kahl said. “Extreme weather is already costing billions of dollars here at home to our DoD infrastructure, and that will increase in the years ahead, at home and abroad.

“And of course there are real questions about energy resilience, especially in the context of great power competition. So for all those reasons, I think climate has to be integrated into our defense strategy.”

Arms sales: The Biden administration is currently reviewing a number of weapons sales to foreign governments that were cleared under the Trump administration, with a pair of sales to Saudi Arabia already halted.

Asked whether a broad review of arms sales to non-democratic governments makes sense, Kahl said: “I do. I think our arm sales need to be aligned not just with our national interests but with our values. ... You have my personal commitment that if I’m confirmed, I will treat the issue urgently because it’s important to me.”

Civilian control of the military: Although it did not come up in the hearing, a major issue facing the Pentagon for several years has been tension between uniformed members of the military and civilians working in the policy shop. In written advanced responses to questions from senators, Kahl said he is committed to ensuring the civil-military balance is properly maintained.

He also raised concerns about the policy shop having shrunk by 25 percent over the last decade, the result of a congressionally ordered headcount reduction at the department.

“I am concerned about these cuts, and if confirmed will review [the policy department’s] missions and current staffing levels to determine whether the professional civilian staff is sized appropriately and whether it is able to recruit and retain an experienced, talented, diverse workforce that can effectively carry out the Secretary’s vision for meaningful oversight of the military,” Kahl wrote. “If necessary, I will seek additional personnel to be assigned permanently to Policy so that we can effectively pursue these national security missions and improve civilian control of the military.”

Aaron Mehta was deputy editor and senior Pentagon correspondent for Defense News, covering policy, strategy and acquisition at the highest levels of the Defense Department and its international partners.

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