The drumbeat has started. On Wednesday, three Republican senators formally asked their colleagues to create a select committee to investigate the attack in Benghazi, Libya, that killed Ambassador J. Christopher Stevens and three other Americans on the anniversary of Sept. 11, 2001.

Congress has every right to look hard at what went wrong with U.S. security in Benghazi, and lawmakers have raised valid questions about the troubling events. But recent history suggests that the most important investigation won’t take place on Capitol Hill. It will be conducted by an independent commission that has already been established, albeit with much less fanfare. This commission, which may report as early as next month, will be most likely to produce the definitive account of the Benghazi attack and shape the long-term U.S. response to it.

Select committees make for good theater and often uncover important facts. But in the national security arena, the independent commissions that have probed the most shocking security lapses — including the 2001 attacks and several devastating bombings of U.S. embassies — have a better record of conducting impartial investigations and bringing about landmark reforms.

This past week’s events follow a pattern that is familiar to me after studying every national security commission created in the past three decades. After weeks of Republican criticism of Obama administration statements about what happened in Benghazi, Sens. John McCain, Lindsey Graham and Kelly Ayotte introduced a resolution to create a select committee composed of four Republican and four Democratic senators.

Graham and McCain, in arguing the need for such a high-powered, high-visibility effort, invoked the select committees that investigated the Watergate and Iran-contrascandals, implying that Obama administration officials may have acted unethically or criminally. Using more superheated rhetoric, McCain added that he wanted the committee to investigate everyone up to and including the president. Graham asserted that Obama had “failed as commander in chief before, during and after the [Benghazi] attack.”

These comments suggest that the Republican senators have prejudged the investigation’s outcome, a conclusion that is only strengthened by their statements that they will do everything in their power to stop U.N. Ambassador Susan Rice from becoming secretary of state if Obama nominates her. In this partisan context, Senate Democrats have little incentive to agree to establish a select committee. Even if such a panel were named, it would fracture quickly along party lines.

A better approach is already in place. Under a 1986 law, the secretary of state must convene an independent commission, called an accountability review board, to investigate any incident involving loss of life or destruction of property at a U.S. mission abroad. Accordingly, in September, Hillary Rodham Clinton appointed a five-member panel led by Thomas Pickering, a highly regarded former senior State Department official.

Independent commissions are often scorned as institutions that do nothing more than help politicians defuse political pressure. But my research shows that this conventional wisdom is wrong. Yes, elected officials sometimes appoint commissions to deflect attention, but in the wake of disasters, these panels typically publish hard-hitting accounts of government shortcomings. They are also usually more capable than congressional committees of producing proposals that gain broad bipartisan support.

Consider the response to the Sept. 11, 2001, attacks. In 2002, the House and Senate intelligence committees jointly investigated those strikes, but their probe was riven by partisan disagreements about whether to press the George W. Bush administration for access to principal witnesses and documents. Media coverage of the report focused on dissenting opinions by no fewer than nine lawmakers, and its recommendations were largely ignored.

By contrast, the independent 9/11 Commission’s unanimous proposal to establish a director of national intelligence was quickly enacted into law, resulting in the intelligence community’s most significant overhaul in six decades.

An earlier independent commission, led by retired Navy Adm. Bobby Inman, charted the way after a spate of deadly bombings at U.S. Embassies throughout the Middle East in the early 1980s. The Inman panel inspired the creation of the first professional security service within the State Department and the establishment of new security standards for the construction and protection of diplomatic facilities. Those standards, which include requirements that buildings be set back at least 100 feet from the nearest street and protected by substantial barriers, are still known as the “Inman standards,” in recognition of the panel’s impact.

The next major bombings of U.S. Embassies occurred in 1998, when al-Qaeda-led attacks killed 224 people, including 12 Americans, in Kenya and Tanzania. A new commission led by William Crowe, another retired admiral, took the executive branch and Congress to task for having failed to provide the money to fully implement the Inman standards, and called for $1.4 billion per year in new spending to complete the job. Crowe’s dogged advocacy led the administration and Congress to adopt the panel’s recommendations. Since then, most U.S. diplomatic facilities have been “Inmanized,” to use the lingo of some department officials.

There’s every reason to expect that the Pickering panel’s report on Benghazi will have a similar outsize impact. The other commission members include Michael Mullen, the former chairman of the Joint Chiefs of Staff; Catherine Bertini, a former undersecretary for management at the United Nations; Richard Shinnick, a former head of State Department building operations; and Hugh Turner, a retired CIA operations officer. Since all five commission members have distinguished, nonpartisan records of public service, their report will be insulated against accusations of bias, and the Obama administration and Congress will have strong incentives to adopt their proposals.

Those recommendations will surely include steps to plug security holes, and rightfully so. But the country would be well served if the commission also considered how to strike the proper balance between diplomatic security and openness. The natural tendency after an act of terrorism is to focus entirely on bolstering security, as the Inman and Crowe panels did. But the long-term result of those earlier reforms has been mixed. Yes, successful attacks on U.S. missions overseas have become less frequent, but at the cost of turning many missions into inaccessible fortresses. Diplomacy has an element of risk, and it’s much harder to project a message of freedom and democracy from behind high walls that say, “Keep out.”

Many Foreign Service officers in the 1980s resisted the Inman proposals because they feared that the security upgrades would make it much harder to conduct diplomacy effectively. Those fears have been validated. Today, our best diplomats continue to recognize that they need to spend much of their time outside embassies to build partnerships with civil society and enhance America’s image. This kind of outreach is particularly important in countries such as Libya that are experiencing dramatic political change. Yet such countries also tend to be relatively dangerous, presenting stark trade-offs between diplomatic security and diplomatic success.

In the wake of the Benghazi attack, it is politically difficult for a public official to argue for doing anything other than tightening security. But the members of the Pickering panel are no longer in government and therefore have more leeway to assess and explain the real trade-offs we face. The commission’s report may represent our best opportunity to forge a new public understanding of how to protect our diplomats while allowing them to meet with local people in the places where they live, work and congregate.

Jordan Tama, an assistant professor of international relations at American University’s School of International Service and a former senior congressional aide, is the author of “Terrorism and National Security Reform: How Commissions Can Drive Change During Crises.”

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Jordan Tama, an assistant professor of international relations at American University’s School of International Service, is the author of “Terrorism and National Security Reform: How Commissions Can Drive Change During Crises.”