What political or legal reasons might explain why a president would not order the release of sensitive investigation files?

1. Executive privilege: the legal shield presidents most often cite

Presidents and high‑level White House officials can assert executive privilege to withhold information from Congress, the courts, and the public; leading summaries and historical treatments identify categories including “investigative files and reports” and internal deliberations, which are routinely invoked to resist disclosure ^{[1] [2]}. Legal commentators and institutional texts emphasize that the privilege rests on separation‑of‑powers interests—protecting candid advice and national security deliberations—and is applied through a balancing test against oversight or litigative needs ^{[2] [1]}.

2. Statutory exemptions and the Presidential Records Act (PRA) create procedural guardrails

The PRA requires presidential materials be categorized and places NARA in legal custody, but it also contains exemptions and procedures that limit immediate public release; certain categories (e.g., confidential communications, statutorily exempt information) may be withheld or require notification to the incumbent and former presidents before disclosure ^{[3] [4]}. Those statutory rules mean a president does not always have unilateral, immediate authority to release or reclassify documents in dispute; instead, release often triggers formal review and potential claims of privilege ^{[3] [4]}.

3. Protecting national security and foreign‑policy information

One central legal justification is the protection of military, diplomatic, or other national‑security secrets: classic executive‑privilege rationales explicitly include “military and diplomatic secrets and foreign affairs,” and such claims can legitimately block release to prevent harm to operations or sources ^{[1] [5]}. When files touch classified programs or intelligence sources, national‑security officials and Justice Department counsel commonly advise restraint or redaction, and courts give deference to the executive on sensitive foreign‑policy material ^[1].

4. Ongoing litigation, investigations, and grand‑jury secrecy

If documents relate to pending litigation or criminal investigations, a president may invoke privilege or cite rules protecting investigative files to avoid interfering with prosecutors, grand juries, or judicial processes; authorities identify “information relating to pending litigation, and investigative files and reports” as a recognized category for withholding ^{[1] [2]}. Courts, however, have limited this protection where demonstrable relevance to criminal proceedings outweighs confidentiality—United States v. Nixon is a persistent touchstone in that tension ^[1].

5. Political incentives: self‑protection, institutional prerogatives, and message control

Beyond doctrinal claims, presidents face political incentives not to release sensitive files: disclosure can damage allies or aides, reveal embarrassing internal deliberations that chill future candid advice, or expose the president to impeachment inquiries or criminal scrutiny. Institutional defenders may frame withholding as protecting the presidency’s ability to function; opponents argue such claims can be used to conceal misconduct. Both narratives appear across historical episodes of privilege disputes ^{[2] [5]}.

6. The DOJ and prosecutorial discretion as a political‑legal constraint

The Department of Justice’s own practices affect what can or will be released or prosecuted: for example, the DOJ has interpreted its policies to constrain prosecution of a sitting president and to shape how executive materials are handled in investigations, which intersects with executive decisions about disclosure ^[6]. Available sources note that the Supreme Court has never definitively declared a president immune from prosecution, but DOJ policies have real practical consequences for how executive‑branch documents are treated during inquiries ^[6].

7. Courts, remedies, and limits on unilateral withholding

Courts can compel disclosure in some circumstances and have rebuked overbroad claims of privilege when evidence is “demonstrably relevant” to criminal proceedings, but judicial enforcement is politically and institutionally fraught; scholars and practitioners emphasize a balancing approach and note that failure to comply with court orders raises constitutional friction and limited remedies ^{[1] [7]}. NPR coverage of post‑order standoffs illustrates that litigation over executive compliance can become drawn out and messy ^[7].

8. Competing viewpoints and political uses of privilege

Legal sources present a split between those who view executive privilege as essential to candid governance and national security, and critics who see it as a tool for concealment or partisan protection. Congressional oversight proponents stress the need for access to perform oversight and impeachment functions, while executive defenders point to separation‑of‑powers interests and specific categories (e.g., internal deliberations, classified content) that deserve protection ^{[2] [1] [5]}.

Limitations: This account summarizes legal doctrines, statutory rules, and political incentives drawn from the provided sources; available sources do not mention every possible motive or give a comprehensive case law catalogue beyond the cited summaries ^{[1] [2] [3]}.