WASHINGTON—As Defense Secretary Pete Hegseth begins his first official day on Monday, he faces a multitude of critical challenges, ranging from international conflicts to domestic security, along with various administrative responsibilities.

One of the immediate tasks on his agenda is to fulfill President Donald Trump’s commitment to bolster the U.S. military presence along the southern border. This includes evaluating whether active-duty forces should engage in law enforcement activities, a practice that has been infrequent in recent times.

Numerous pressing issues will demand his focus, including the formulation of the Pentagon’s substantial budget, decisions regarding aid for Ukraine, support for the ceasefire in Gaza, and troop placements in the Middle East. Furthermore, Hegseth must also navigate Trump’s instructions to eliminate diversity initiatives within the federal government and streamline operations by cutting out inefficiencies while removing any remaining personnel aligned with the Biden administration.

In a communication to service members shortly after his swearing-in ceremony, Hegseth acknowledged the obstacles he anticipates. Many of these issues mirror those his predecessors have encountered, such as realigning the military from a long-standing focus on the Middle East and improving deterrence against China. Ongoing conflicts, particularly following the October 2023 assaults on Israel by Hamas, have complicated this transitional phase.

He has also emphasized the importance of fortifying the defense industrial base and achieving compliance with Pentagon audits, reiterating the aim for the U.S. to maintain its status as “the strongest and most lethal force in the world.”

Hegseth visited the Pentagon unannounced after his inauguration at the Eisenhower Executive Office Building, with no media present for his entrance. The Pentagon later shared a photograph highlighting that he is prepared to begin his duties on behalf of America’s military personnel.

Already, his support staff has met with military leaders, including Gen. CQ Brown Jr., the Joint Chiefs of Staff chairman. However, Hegseth is set to experience an intense learning curve as he endeavors to quickly familiarize himself with the activities of the 2.1 million service members and 780,000 civilians within the department, many of whom are stationed overseas in active combat zones.

Additionally, issues related to military culture, which Hegseth has critiqued in his previous media roles, are expected to arise soon.

Here are some major challenges that Hegseth, who was confirmed in a pivotal vote by Vice President JD Vance, will confront immediately:

**Border Deployments**

To align with Trump’s directive on border security, Hegseth will be inundated with information regarding troop availability, the requirements of the Border Patrol, and logistical considerations including transportation, housing, and sustenance for deployed troops. He will need to ensure these deployments do not compromise other national security priorities.

A significant early decision will revolve around whether to advise that active-duty forces at the border participate in law enforcement actions, a recommendation that military leadership has historically been cautious of making. Under the Posse Comitatus Act, active-duty military personnel are generally prohibited from performing law enforcement tasks on domestic soil. Trump has issued an executive order requiring his defense and homeland security secretaries to evaluate whether invoking the 1807 Insurrection Act, which permits military use for civilian law enforcement during emergencies, is warranted.

Past deployments have seen troops engaged in logistical support roles, such as transportation and reconnaissance, thereby allowing Border Patrol agents to manage interactions with migrants.

**Transgender Troops**

In his initial executive action, Trump has reverted protections for transgender service members that President Biden had put in place after reversing an earlier ban against their service. This ban faced legal scrutiny in the past, leading advocates to prepare for renewed litigation if transgender personnel face discrimination once again. Although Trump has not explicitly reinstated a ban, his revocation of existing protections is perceived as a precursor to future actions against transgender troops.

The exact number of affected troops remains unclear, as the Defense Department does not maintain precise records on transgender service members since not all transgender individuals disclose their status in military documentation.

**Budget and Ukraine**

Hegseth will need to navigate the complexities of the Pentagon’s budget, currently sitting at around $850 billion. Both he and Trump have voiced aspirations to enhance military lethality while advocating for cuts against wasteful expenditures. As Hegseth formulates the budget, it will be under scrutiny to assess how waste is being eliminated.

Security assistance for Ukraine is intricately tied to these budget discussions. With the State Department implementing a freeze on almost all foreign aid, it remains uncertain if military assistance for Ukraine will follow, unlike the waivers given to countries like Israel and Egypt. The Biden administration previously allocated over $66 billion in military support to Ukraine during its conflict with Russia—$3.85 billion of which is still available from authorized funding for additional weaponry. Hegseth and Trump must decide how to proceed with these funds amidst the foreign aid freeze.

**Diversity, Equity, and Inclusion Rollbacks**

Hegseth will oversee the Pentagon’s execution of Trump’s executive order aimed at dismantling diversity, equity, and inclusion initiatives. Military officials have expressed concerns regarding potential repercussions for perceived political affiliations, especially in light of Hegseth’s commitment to curtail DEI programs.

During his Senate hearing, he criticized DEI policies as divisive and argued they undermine merit-based systems. In a recent post on social media platform X, Hegseth reiterated that the Defense Department would comply fully with Trump’s directives, stating that any non-compliance would lead to termination of employment.

While officials mention that the Defense Department does not have full-time employees dedicated to DEI efforts, they expect minimal lay-offs. Senior leaders are currently reviewing their online resources to remove references to diversity, although the lack of cohesive guidance has led to inconsistent implementation across different branches. For example, the Army temporarily took down its sexual assault guidelines before reinstating them later.

Hegseth has previously criticized the inclusion of women in combat roles, claiming standards were lowered for them—a notion that lacks factual backing. He has, however, moderated his stance in response to significant opposition from lawmakers and stated he is unaware of Trump’s plans to reverse policies allowing women into combat roles, focusing instead on reviewing operational standards.

**Reproductive Care**

After the Supreme Court’s 2022 decision dismantled the constitutional protections for abortion established by Roe v. Wade, former Defense Secretary Lloyd Austin implemented a policy that permitted service members to take leave and receive reimbursement for travel costs to access reproductive services, including abortions, if stationed in areas where such services were restricted.

It remains uncertain whether Hegseth will make changes to that policy, particularly regarding reimbursement provisions. This policy has been infrequently utilized, with protective privacy laws preventing the Defense Department from revealing specifics about the nature of medical travel.