The decision by Jesse Jackson Jr. to resign from Congress marks a personal tragedy and a political loss. The tragedy is his; the loss is the rest of ours. Newly reelected after serving for 17 years in Congress, Jackson, who has been struggling with bipolar disorder, decided that he could no longer adequately represent his constituents.

He also acknowledged an embarrassing, ongoing federal investigation into the possible misdirection of campaign funds: “I am doing my best to . . . cooperate with the investigators and accept responsibility for my mistakes,” he wrote in his resignation letter, “for they are my mistakes and mine alone.”

The media has covered the resignation as a personal fall from grace, but Jackson’s resignation will be felt widely in progressive circles. He is a rare leader who could both inspire a crowd and explore an idea. He is a principled but original progressive, one who has read widely in U.S. history. He probed deeply into the interplay of race, division and democracy in our past and present but could make an expert’s knowledge clear to the ordinary citizen.

As an independent progressive leader in Congress, Jackson — the oldest son of the Rev. Jesse Jackson — has had the frustration of fighting on the right side of losing policy battles. He challenged the Southern political strategy and trickle-down economics of the right. But he also questioned conservative and Wall Street Democrats who sought to tack with the prevailing reactionary winds. This commitment helped increase his national exposure even as it made it harder for him to rise in a city where conscience is often viewed as an occupational liability.

Jackson voted against President George W. Bush’s war on Iraq. He also protested the constitutionality of a president waging war without a formal declaration from Congress and joined a court action against the constitutionality of the invasion. After the scope of the debacle and the lawlessness in the war on terror became clear, he pushed hard for a congressional inquest that would establish accountability to the Constitution and the law.

Jackson challenged the ruinous corporate trade policies, pushed by presidents of both parties, that have proved devastating to working families. He constantly questioned the priorities of a country intent on policing the world while failing to invest in vital needs at home.

After the conservative Gang of Five on the Supreme Court shamefully stopped the vote count in Florida in Bush v. Gore, Jackson led not simply the condemnation of the indefensible decision but also the demand for reform of our deeply flowed electoral process. He proposed a constitutional amendment to establish a national right to vote and a comprehensive reform agenda to ensure that everyone could exercise that right confident that their vote would be counted.

In 2001, Jackson co-authored with longtime aide Frank Watkins, a remarkably original study of U.S. politics titled “A More Perfect Union.” There he urged progressives to take up their own “constitutional politics.” The right, he observed, promoted dozens of constitutional amendments, from prayer in the school to balancing the budget to the repeal of a woman’s right to choose. This enabled them to argue not policy — how to achieve a goal — but principle, why that goal or value was essential.

So Jackson and Watkins proposed eight constitutional amendments, many similar to the Economic Bill of Rights championed by Franklin Roosevelt coming out of the Great Depression and World War II. These included the right to vote, the right to “health care of equal high quality,” the right to “public education of equal high quality,” a reintroduction of the Equal Rights Amendment, a full employment amendment and an amendment calling for the right to “enjoy . . . a clean, safe and sustainable environment.” Now, as a mass movement for a constitutional amendment to rein in big money and corporate power builds in the wake of the Citizens United decision, Jackson seems prescient in understanding the political and moral value of pursuing new constitutional rights.

There is one more aspect to the congressman’s story that is worth reflecting on: our media narratives on the subject of mental illness. Far too many talking heads offered long-distance prescriptions on a subject they knew little to nothing about; far too many media outlets demanded that Jackson get back to work, a demand never made of public officials who have suffered physical illness; far too many pundits seemed somehow insulted that the voters of Jackson’s district seemed willing to give him time to try to heal.

At a time when too many of our elected officials are more lemming than leader, Jesse Jackson Jr. was not afraid to think originally and lead forcefully. We can only hope that he will overcome the demons and mistakes that now plague him and once more be able to contribute his energy and intelligence to forging a more perfect union.