NASHVILLE, Tenn. — For days now, Kentucky Sen. Rand Paul has sought to dismiss criticism over similarities between his speeches and material on Wikipedia, accusing “footnote police” and “hacks and haters” of unfairly criticizing him.

There are reasons he’s been speaking out: in the long run, allegations of plagiarism could be used against him in a presidential campaign, and, in the short term, castigating his critics, particularly on the left, could fire up his loyal backers — and donors.

It all began last week when MSNBC host Rachel Maddow accused the senator of lifting passages about the 1997 science fiction film “Gattaca” from the movie’s Wikipedia entry when he made a speech on Oct. 28 supporting Virginia gubernatorial candidate Ken Cuccinelli. The passages are similar, with only a few words changed here and there.

Then the website Buzzfeed reported that a Paul speech in June describing the movie “Stand and Deliver” also included substantial similarities to its Wikipedia entry, and late-night comics — such as Comedy Central’s “The Colbert Report” — poked at him.

Questioned last week about the matter, Paul initially downplayed the allegations. He told the Fusion television network that he had given proper credit to the film’s writers.

By Sunday, he was acknowledging sloppy speechwriting while criticizing those who had made the plagiarism allegations.

“The footnote police have really been dogging me for the last week. I will admit that,” he told ABC’s “This Week.” “And I will admit, sometimes we haven’t footnoted things properly.”

He added: “I’m being unfairly targeted by a bunch of hacks and haters.”

A comparison of his Oct. 28 speech and Wikipedia shows the parallels.

In that speech, Paul used the plot of “Gattaca” as part of an argument that abortion rights could lead to eugenics policies.

For example, he began summarizing the plot by saying: “In the not too distant future, eugenics is common and DNA plays a primary role in determining your social class.”

Those remarks closely resembled the Wikipedia entry, and video of the speech shows the senator making air quotes with his hands around the opening phrase, which is how the text appeared on the website. Paul went on to use other elements that closely matched the Wikipedia entry.

The senator told “This Week” that he doesn’t consider speeches to carry the same rules of attribution that written pieces do, and said that he took offense to any suggestion of being intentionally dishonest or misleading.

Paul, who is considering a 2016 presidential bid, need only look to the current administration for cautionary examples of how allegations of plagiarism can affect a campaign.

Vice President Joe Biden ended his first presidential bid amid allegations that he plagiarized material from a British politician in a speech at the Iowa State Fair in 1987. Biden at the time called the failure to attribute the quote to then-Labour Party leader Neil Kinnock an oversight.

And President Barack Obama during the 2008 campaign for his first term in office had to fend off charges from rival candidate Hillary Clinton that he had lifted lines from an address by his friend, Massachusetts Gov. Deval Patrick.

Clinton in a debate ridiculed Obama as a candidate of “change you can Xerox,” but the plagiarism allegation did not end up having a major effect on the race.