Today millions of Americans will watch five hours of televised congressional hearings. Trump supporters will look for evidence of a witch hunt pushed by overzealous partisans willing to do anything to remove the president from office. Many on the left by contrast will look for some sign that former special counsel Robert S. Mueller III thinks President Trump did something worthy of impeachment. And the Democrats want to present a powerful narrative about presidential misconduct without losing control of the process to more zealous forces.

But can these hearings actually make a difference?

Maybe. While they are unlikely to instantly shift public opinion on the question of impeachment, hearings may give Congress an opportunity to reassert its authority at a time when the executive branch is using all the powers at its disposal to demean individual members and render their legislative powers meaningless.

Historically, televised congressional hearings have offered a rare chance for Congress to steal the spotlight from the president, giving Americans an occasion to see a complicated and diverse branch of government at work. This creates an opportunity to generate meaningful conversations about public policy and to raise questions about executive overreach. But there is risk as well: When viewers sense that hearings are simply a forum to build the celebrity of members of Congress, they can lose their legitimacy and destroy careers.

Over the course of the 20th century, media savvy presidents from Theodore Roosevelt to Woodrow Wilson to Franklin Roosevelt harnessed technological advances, from radio to motion pictures, to give themselves an unprecedented ability to reach Americans with their message. Television only intensified this presidential authority by turning the White House into a production studio and the president into a prime time star.

Members of Congress understood that, in the words of Sen. J. William Fulbright, television coverage of the presidency threatened the “traditional constitutional balance” between the two branches of government. With 535 individuals versus one president, Congress lacked the capacity to draw the spotlight away from its near-permanent focus on the White House in the television age.

But that didn’t stop Congress from trying. And televised congressional hearings became one tool for matching the presidential message-making machine. According to one observer in 1961, the post-WWII “upsurge in congressional investigations primarily reflects an attempt on the part of the legislature to restore a balance of power in the area of publicity.” Investigations were a “form of entertainment” that captured the public’s attention, providing an avenue for Congress to reclaim its place in the public political conversation.

Such hearings also dangled the prospect of stardom for members of Congress. Twenty-one days of dramatic House Un-American Activities Committee hearings in 1948, for example, made new congressman Richard Nixon famous as he investigated the claims that State Department official Alger Hiss was a communist. Similarly, the 1950 investigation into organized crime led by Sen. Estes Kefauver may have used television to expose “the face of evil,” according to one publication — but it also helped to elevate Kefauver to the vice presidential nomination in 1956.

Thanks to this tantalizing prospect, turning investigations into televised drama became a common practice for congressional committees in the 1950s. But this technique sparked a debate: Was TV a new tool for democratic governance or a sensationalist ploy that was a “prostitution of the true function of the legislative committee,” as one critic fretted?

The 1954 performance by the infamous redbaiter Joseph McCarthy supported the latter conclusion. The senator from Wisconsin had capitalized on the public panic and anxiety surrounding communism in the postwar period to become a household name. Then, over 36 days of televised hearings, he dug into whether the U.S. Army was wracked by communist subversion. But McCarthy went too far: When Special Counsel for the Army Joseph Welch responded to McCarthy’s badgering with “Have you no sense of decency sir?” he exposed that McCarthy’s professed concern about communism was a self-serving grasp for power, not a genuine national security fear. The exchange prompted newscaster Edward Murrow to declare, “It is necessary to investigate before legislating. But the line between investigation and persecuting is a very fine one, and the junior senator from Wisconsin has stepped over it repeatedly.”

While McCarthy’s overreach curtailed his career, it did not deter congressional committees from the practice. While the public largely ignored specialized hearings on the nuances of particular bills, Americans eagerly tuned in to watch dramatic inquisitions and confrontations like the February 1966 encounter between Lyndon Johnson’s administration and critics of the Vietnam War like Fulbright.

In fact, Johnson feared that such hearings could become the ultimate tool for Congress to challenge presidential authority, gain prestige and advance policy that challenged his own. To minimize their impact, he pressured CBS to discontinue coverage and staged his own counterprogramming to distract from the hearings.

Nothing more vividly illustrated the accuracy of Johnson's concern than the Watergate hearings that ended up deposing his successor. The secret to their success was not just the bombshells unleashed during the testimony of figures like John Dean and Alex Butterfield (who revealed the existence of the White House tapes). Rather, it was in the seriousness that pervaded the occasion.

Senators resisted playing to the camera, instead almost grimly focusing on uncovering the truth and holding the president accountable. They avoided the petty overreach that had toppled McCarthy, and emphasized the integrity of the fact-finding process. The instantly famous line by Republican Sen. Howard Baker underscored this emphasis on facts: “What did the president know and when did he know it?”

The post-Watergate Congress ultimately made the simultaneous quest for media coverage and determination to investigate even more central to its operations. A 1975 Report on “Congress and Mass Communication” urged expanded coverage of congressional activities on television to “bring meaningful information more directly to more of our citizens.” According to Sen. Lee Metcalf (D-Mont.), who chaired the joint committee exploring this possibility, Congress needed to interrogate any “customs or other aspect of our operation that might discourage the news media or the public generally from seeing — and understanding — the activities and role of the National Legislature.” The underlying goal: to use new media to bring accountability and transparency to Washington.

But this actually opened more paths for personal and partisan warfare. As Rep. George Miller of California recalled, these post-Watergate reforms “destroyed the institution by turning the lights on.” Congressional representatives soon became household names, but they did so by using televised coverage of legislative proceedings and investigations to gain personal celebrity, not to cultivate public trust. While Congress emerged from the Watergate hearings as a celebrated “institution worthy of respect,” embracing television over the next decade actually eroded these sentiments. Why? Because by the 1990s, spectacle and aggressive grandstanding were a ticket to stardom, both on television and in party politics, and investigations into presidential misconduct had become a tool of partisan warfare.

And herein lies the challenge today: Mueller’s testimony will turn the spotlight on Congress, but what message will the people questioning him send? Can the Democratic leadership use this as an opportunity to convince the American public that they are working to safeguard public interest rather than promoting their own partisan agenda?

If Democrats take the high road of reasserting congressional authority, the hearings may allow them to finally begin to hold Trump accountable. But if they aim their comments solely at the partisans watching at home, they may convince Americans that the conflict with Trump is more about scoring political points than imposing needed oversight on a president flagrantly violating the law.