Hillary Clinton speaks at the African Methodist Episcopal Church's general conference in Philadelphia on July 8. (Matt Rourke/Associated Press)

ST. LOUIS — Hillary Clinton will call for a constitutional amendment to "overturn Citizens United" in her first 30 days as president and plans to make that announcement today to progressive activists at the annual Netroots Nation conference.

"I will also appoint Supreme Court justices who understand that this decision was a disaster for our democracy," Clinton will say in a video message, scheduled to run near the end of today's final keynote session. "I will fight for other progressive reforms, including small-dollar matching and disclosure requirements. I hope some of the brilliant minds in this room will seek out cases to challenge Citizens United in the courts."

In a statement accompanying the announcement, Clinton pledges to promote Securities and Exchange Commission "rulemaking requiring publicly traded companies to disclose all political spending to their shareholders" and to sign an "executive order requiring federal government contractors to fully disclose all political spending." She has discussed versions of those ideas on the campaign trail, but the forum of Netroots Nation — a conference in its 11th year that she visited in person only once — was a striking place to make the statement.

Clinton's campaign previewed the announcement for some progressive groups, which gave it their seal of approval. "Hillary Clinton's commitment to overturning Citizens United, and her other systemic proposals like public financing of congressional elections, are key to improving our chances of victory on every other issue," said Marissa Barrow, a spokeswoman for the Progressive Change Campaign Committee.

Since 2010, the Citizens United decision has become a metonym for a series of conservative Supreme Court decisions that unwound campaign finance regulations. Democrats have repeatedly tried to pass disclosure measures, as well as an amendment to the Constitution, intended to reverse the decisions. Republicans, often led by Sen. Ted Cruz (Tex.), have characterized those efforts as attacks on the First Amendment.

Even though the case was fought over an anti-Hillary Clinton documentary, Sen. Bernie Sanders (Vt.) became its most prominent critic in the 2016 primaries. He never finished a speech without mentioning Citizens United v. Federal Election Commission, blaming it for the money gushing into politics, and pledging to appoint a Supreme Court that would undo it.

"I know that many of the people in this room supported Sen. Sanders in the primary," Clinton will tell Netroots activists in the video, as footage of the senator and his wife, Jane, a popular campaign surrogate, plays behind her. "I'm looking forward to hearing from you, learning from you, and working with you."