As Washington gears up to commemorate the 50th anniversary of Dr. Martin Luther King Jr.'s historic "I Have a Dream" speech later this month, one thing might be missing from the celebrations: the speech itself.

A full, unedited video clip of the speech is tougher to find than you might think, because of copyright disputes that date back almost as far as the speech itself.

"We were shocked to find that it was very difficult to find a full copy of Dr. King's speech on YouTube," said Evan Greer, a campaign manager at Fight for the Future, an Internet free-speech advocacy group. In January, the group posted the full-length speech on Vimeo in an act of "civil disobedience" coinciding with Martin Luther King Day. The video was promptly removed for violating Vimeo's terms of service, Greer said, but a version on YouTube has managed to avoid detection and remains up on the site, having accumulated more than 80,000 views.

"When I sat down to make this video, I'm not sure I had ever seen the whole speech," Greer said. "We thought it was incredibly important that any young person be able to hop online and watch this speech … that is as relevant today as it was when it was written."

Months after the August 1963 March on Washington, King himself sued to prevent the unauthorized sale of his speech, purportedly in an effort to control proceeds and use them to support the civil-rights movement. In 1999, the King family sued CBS after the network produced a video documentary that "used, without authorization, portions of … King's 'I Have a Dream' speech." A divided Appellate Court, in reversing a lower court ruling, held that the speech was not a "general publication," despite its huge audience and subsequent historic importance. The speech instead qualified as a "limited publication," the court said, because "distribution to the news media, as opposed to the general public, for the purpose of enabling the reporting of a contemporary newsworthy event, is only a limited publication."

The ruling was narrow, and CBS and the King estate settled the case before the lower court could reconsider, leaving the copyright of the speech in a somewhat confusing legal situation. A CBS press release dated July 12, 2000, discusses the agreement that allowed the network to "retain the right to use its footage of the speeches" from the march and license it to others in exchange for an undisclosed contribution to the Martin Luther King, Jr., Center for Nonviolent Social Change.

In 2009, EMI Publishing cut a deal with the King estate to help ensure that the speech was "accorded the same protection and same right for compensation as other copyrights." EMI was sold in 2011 to a consortium headed by Sony. The King Center did not respond to requests for comment.

The result is that viewing the whole speech online may remain difficult until 2038, when the current copyright expires, because of laws that protect intellectual property long after the author is deceased.

"These expiration dates are incredibly complicated and constantly changing," said David Sunshine, an intellectual-property lawyer with Cozen O'Connor. "Congress always moves the goalposts on these things when lobbying groups come in."

The Copyright Term Extension Act, passed in 1998, and more commonly known as the Sonny Bono Act or Mickey Mouse Protection Act, did exactly that. Worried about its expiring copyrights on early Mickey Mouse productions, the Walt Disney Company helped spur Congress to stretch the length of copyright protection from the life of the author plus 50 years to life plus 70 years. King was killed in 1968, which means the copyright on his Dream speech won't expire until 2038.

So will King's dream be heard the day of his anniversary? That depends on where you want to view it—and how much of it you want to see. Much of what is available shows only fragments of the speech. Some, like the History Channel, note that copyright prevents the presentation of a full version.

Networks and other news organizations can air segments of the speech under the doctrine of "fair use," because they can justify it as substantially newsworthy, Sunshine said. (CBS aired short excerpts this past weekend on its Sunday Morning news show.) But airing the entire speech—all 17 minutes—could blur those lines.

"The less you play, the easier it is to argue it's fair use, generally speaking," Sunshine said. And networks such as CBS are probably more inclined to pay the licensing fee than to shell out hundreds of thousands of dollars to test the waters on a fair-use claim. This creates a noticeable divide between television corporations that could afford to legally challenge the copyright protections (but may not want to, because they do not need to show the full speech) and others, who lack means to challenge that restriction, Sunshine said.

Greer argues that blocking people from watching one of the most important speeches in American history online in 2013 is an injustice that King himself wouldn't tolerate. And it could deprive many young people of the opportunity to learn first-hand—through watching video—about a critical moment in the civil-rights movement.

"Most people are going to turn online where they want to watch it and share it," Greer said. "It's incredibly important for people to find it there and share it with their community."

Buying a DVD of the speech remains an option. Amazon currently lists copies as low as $13.41.