By Todd Shields, Bloomberg News (TNS)

WASHINGTON — Radio stations and cable TV will soon need to disclose online the political ad spending of Donald Trump, Hillary Clinton and other candidates — but don’t expect instant clarity.

The U.S. Federal Communications Commission on Thursday is set to bring other media in line with broadcast television, which began disclosing political spending online during the last presidential election campaign. The proposed order, backed by FCC Chairman Tom Wheeler, includes satellite TV and is expected to be approved.

“For too long, the public could barely access the ‘public’ file. It was maintained only on paper in file cabinets at the actual radio and TV stations,” Wheeler said in a Jan. 7 blog post. “In the Internet age, that didn’t make any sense.”

The order requires the disclosure of ad spending on behalf of candidates for local, state and federal public office on an FCC website but doesn’t specify how the data must be reported. Information may be entered in a hodgepodge of formats, possibly with hand-scribbled amendments, leaving a daunting task for analysts, journalists and others collating totals and divining trends.

“Symbolically it’s great,” said Tim Francisco, a professor at Youngstown State University in Ohio, who has helped students track campaign spending. “We’re increasing the number of files available, but we’re not making them any easier to access.”

The FCC already requires orderly records “of all requests for broadcast time made by or on behalf of a candidate for public office” and the order would move the documentation from paper to online files.

The FCC left out of the order any requirement for the use of machine-readable data. The priority is to bring more information online before considering other changes, said Neil Grace, an agency spokesman.

Measures advanced by Wheeler, a Democrat, typically pass because his party controls three votes on the five-member panel. Broadcasters and cable operators speaking through trade groups didn’t object to placing reports online and asked for eased requirements for smaller operators.

The proposal will probably pass because it doesn’t face opposition and the online requirement hasn’t burdened TV stations, said Andrew Jay Schwartzman, a Washington-based lawyer who works on disclosure issues with the Institute for Public Representation at the Georgetown University Law Center.

The FCC hasn’t forced the disclosure of anonymous donors who fund independent groups behind some political ads, as requested by some policy advocates and members of Congress.

In a Jan. 20 letter, 170 of the U.S. House’s 188 Democrats urged Wheeler to force the disclosure of what they called “the true sponsors” of political ads: “those who contributed the money to pay for it.”

“Groups spending money to influence our elections should be required to publicly release their donors,” said the letter signed by Reps. John Yarmuth, of Kentucky; Anna Eshoo, of California, a leader for telecommunications legislation; and Steny Hoyer, of Maryland, the No. 2 Democrat in the House. The FCC has power to reverse an earlier agency decision and demand fuller disclosure, they said. The agency is reviewing the letter, said Grace, the spokesman.

The disclosure issue has dogged Wheeler, a Democrat appointed by President Barack Obama. In 2013, Republican Sen. Ted Cruz, now a presidential candidate, blocked a confirmation vote for Wheeler after asking whether he would use the agency to regulate political speech. Cruz, of Texas, relented after Wheeler in a meeting told him that expanding political-ad disclosure wasn’t a priority, according to a statement from Cruz. Grace, the agency spokesman, declined to comment about the meeting.

Democrats have pushed legislation to uncover donors funding independent groups airing ads. Republicans, who control Congress, have blocked the legislation, arguing it poses a threat to free speech. The battle has been raging since the Supreme Court’s 2010 decision in Citizens United that struck down decades-old restriction on corporate and union money in campaigns.

©2016 Bloomberg News. Distributed by Tribune Content Agency, LLC.

Photo: U.S. Democratic presidential candidate Hillary Clinton takes a photo with a supporter at a campaign event in Decorah, Iowa, January 26, 2016. REUTERS/Rick Wilking