Today, the mantle of leftist activism in the Congressional Progressive Caucus is led by a quartet of Democratic congresswomen of color, known as “the Squad.” While some herald them as the “future of the Democratic Party,” Reps. Ilhan Omar (Minn.), Ayanna Pressley (Mass.), Rashida Tlaib (Mich.) and Alexandria Ocasio-Cortez (N.Y.) have more frequently been castigated by extremists, harshly criticized by many in the mainstream media and abandoned by would-be allies.

This is a notable shift from how leftist voices in Congress have functioned in the past. During the late 1970s and throughout the 1980s, the Congressional Black Caucus (CBC) had an outsize voice in the Capitol. It expertly used the media to bring what had been perceived as “radical left” issues into mainstream political discourse. With just over 20 members during the peak of its influence in the mid-1980s, the group consistently voted as a bloc to advance a muscular agenda of social justice and economic reform that led fellow legislators to christen them “The Conscience of Congress.”

The Squad continues the work of the CBC, advocating for issues that appeal to large segments of the general public. So why the hostility surrounding their leadership today? The CBC once bolstered the “radical” ideas of its members, helping individuals build public support and navigate partisan opposition. But now the caucus and other party leaders have abandoned the Squad in a move that undermines the rich tradition of activist-legislators who, at key inflection points in our history, have forced Congress to not just have a conscience but to act on it.

Consider, for example, the career of congressman George Thomas “Mickey” Leland, who was a 44-year-old African American Democrat from Texas when he died 30 years ago this month in a plane crash on a humanitarian delegation to an Ethiopian refugee camp for displaced southern Sudanese. Following his death, journalists, diplomats and his congressional colleagues eulogized him as a champion for the homeless, hungry and impoverished of the world. They celebrated him as a true “citizen of humanity.”

Despite facing criticism and opposition throughout his career, Leland advanced a range of radical proposals by working with the CBC to build alliances with grass-roots organizations, trade unions and their congressional colleagues to shape the public narrative in their favor.

He first set his sight on foreign policy. Well into the 1980s, economic sanctions on South Africa had been considered a radical, impractical proposal in Congress, and one that was antithetical to U.S. Cold War interests. South Africa, despite its repressive race-based laws, was a Cold War ally and economic partner. When Leland and the CBC condemned the apartheid regime, conservatives in Congress and officials in the Reagan administration called them racist and unpatriotic.

However, the CBC led protests outside of South Africa’s Washington embassy, pressed U.S. corporations to divest from South Africa and continually spoke out in the Capitol against U.S. support for the apartheid regime. It worked. Congress passed the Anti-Apartheid Act of 1986, despite opposition and a formal veto by President Ronald Reagan, who erroneously believed that the end of South Africa’s white-minority regime would open the door to communist rule.

In myriad other instances, Leland built support within and beyond the CBC. He initially faced widespread opposition to his proposal for direct U.S. government-sponsored food aid to Marxist-ruled Ethiopia, gripped in the throes of a historic famine. But he crafted a media campaign and lobbied his colleagues on the issue, eventually gaining bipartisan support on an aid package of more than $800 million.

This was not an easy sell to Congress during the Cold War, but Leland, buttressed by his CBC colleagues, insisted that as a land of plenty, the United States had a moral obligation to provide direct food aid, and that working directly with the Ethiopian government, regardless of its ideology, was morally correct. As chair of Congress’s Select Committee on Hunger, Leland held hearings that were unusually well-attended, with CBC members amplifying his call to aid Ethiopia.

Leland pushed hard throughout the 1980s for renewed diplomatic ties with Ethiopia, which he believed would make it easier to facilitate humanitarian assistance. It was a controversial idea, since he simultaneously supported politically isolating South Africa. Numerous Republicans labeled Leland a hypocrite for pursuing peace with Ethiopia’s Mengistu Haile Mariam and shutting the door on dialogue with South Africa. But Leland steadfastly insisted that while Ethiopia’s Marxist government was at odds with the United States for ideological reasons, South Africa, an ally, was so violent and oppressive that it was immoral for the United States to continue to support it.

To him, the United States must hold its allies to a higher moral standard than its adversaries, and it must never be a partner to oppression.

Leland used similar tactics to help bring other then-radical issues from the grass roots into the political mainstream in the areas of social and economic justice, the environment, and political developments in the Global South. He and his progressive colleagues in and beyond the CBC led the opposition to Reagan’s illegal aid to the Contras in Nicaragua and advocated for an end to the U.S. embargo against Cuba.

On myriad issues, from Native American land rights to prescription drug costs and minority representation on television, Leland’s radical prescriptions gradually became legitimate legislative issues or matters of mainstream public debate.

He naturally could not be successful on all of his issues, but he brought them to the fore and his colleagues supported his right to advance his cause.

And herein lies the difference between Leland and the Squad today.

The four women of the Squad vary with respect to their radicalism, but they each, like members of the CBC during the 1970s and 1980s, come from a radical tradition. They have succeeded in elevating the discourse on concentration camps on the border, Islamophobia within the media and the Trump administration, and health care as a human right. Through their savvy use of social media and a refreshing willingness to engage directly and honestly with constituents, they have also reframed the narrative around key political issues, such as student debt relief, the Israeli-Palestinian conflict, human rights and climate change. Recent polls suggest the public takes them seriously and even agrees with many of the policy proposals they advance.

But Leland had the organizing and support of the CBC to help him transform his ideas into legislative action. Given this context and history, the Black Caucus’s failure to vocally and unequivocally support these freshman activist legislators is disheartening, as they assume the role of the “Conscience of Congress” by embracing many of the same tactics, issues and political platforms that brought the Black Caucus its significant influence in U.S. domestic and foreign affairs during the 1980s.

Members of the CBC and fair-minded legislators on both sides of the aisle should support their colleagues and foster honest intellectual debate in lieu of extreme partisanship, divisiveness and derision when it comes to matters on which they may disagree.

With the ever-expanding sway of corporate money and lobbyists in Congress, it is imperative that we have representatives that are, in the words of Rep. Shirley Chisholm, the late activist, legislator, presidential candidate and Black Caucus member, “unbought and unbossed.”

Leland and his fellow caucus members proved that today’s progressive radicalism in Congress may be tomorrow’s mainstream domestic or foreign policy platform. Congress must make space for that potential evolution of values by letting its conscience be its guide.