Congressional probers seldom admit to having anything but the noblest motives, but it's hard to deny that investigations have political value — either for raising the profile of the legislators, or for undermining the other party when it controls the White House. As political scientists Douglas Kriner and Liam Schwartz found in a 2008 study, investigations increase by 12 percent in years when there's a divided government, and the days devoted to hearings increase from 12.28 to 19.92, a 62 percent difference.
After the Democrats seized control of Congress in the 2006 midterm elections, for example, they launched an onslaught of investigations against GOP President George W. Bush's administration, holding 81 hearings in the first two months of the session on subjects related to the Iraq war, including substandard conditions at Walter Reed Army Medical Center. That's not to say that those investigations were unjustified. But they also had strategic political value. The multiple probes caused a lot of difficulties for an administration that had used "support the troops" as its political mantra, Kriner and Schwartz wrote.
Not surprisingly, after Republicans regained control of the House in 2010 and the Senate in 2014, there was a similar uptick in investigations of the administration of Democratic President Barack Obama. After the 2012 terror attack on the U.S. consulate in Benghazi, Libya, in which four Americans died, Congress conducted more than 30 hearings on the attack, involving 10 different committees and 250-plus witnesses [source: Cottle].
That included a two-year-long House probe which didn't report its findings until July 2016, in the midst of the presidential election race in which one subject of the probe, former Secretary of State Hillary Clinton, happened to be the Democratic candidate. While the final report didn't contain any proof of wrongdoing by Clinton, it certainly didn't help her with voters to bring up the subject [source: Collison].
Sen. Sam Ervin, D-N.C., chairman of the committee that investigated Watergate, once observed that investigations sometimes serve as the "catalyst" to get Congress and the public to support vital reforms. But in other instances, he warned, probes also provided "a platform for demagogues and the rankest partisans" [source: U.S. Senate].