David Clarke. Chip Somodevilla/Getty Images More than 50 Democratic House of Representatives members are urging Homeland Security Secretary John Kelly to reject the possible appointment of Milwaukee County Sheriff David Clarke to a top-ranking Homeland Security position.

In a letter addressed to Kelly sent Wednesday, the Democrats noted Clark's past controversial statements about the "Black Lives Matter" movement, which helped his rise to conservative media fame, and criticized him for the four deaths that happened within a span of six months at the Milwaukee County Jail, which he oversees.

Clarke's profile rose during the course of the 2016 campaign when he spoke at the Republican National Convention, served as a surrogate for then-Republican presidential nominee Donald Trump on TV, and campaigned for Trump around the country.

"All the time when these people were dying, he was stumping for Donald Trump," Democratic Rep. Gwen Moore of Wisconsin, one of the leading signatories of the letter, told Business Insider. "And so clearly, he wanted an appointment with the Trump administration. He had calculated that he wasn't going to run for Milwaukee County Sheriff anymore. He was going to seek an appointment."

"He said there was no way he was not going to be loyal to Trump," she continued. "And of course, Trump appreciates loyalty, even beyond competence. It seems loyalty is a greater test for the Trump vetting process than competence. Maybe he will in fact continue to be appointed despite clear evidence that he can't even manage a small county, much less Homeland Security for the nation."

When asked about the letter, Homeland Security Department spokesman David Lapan told Business Insider that the agency does not "comment on correspondence to" Kelly.

"We'll respond to the members as appropriate," he added.

Last week, Clarke told WISN radio host Vicki McKenna that he would work in Homeland Security's Office of Partnership and Engagement as a liaison to law enforcement agencies, saying he'd would start the job in June.

"I'll be a liaison with state and local governments and with the private sector, and one that's really near and dear to me — liaison with the state, local and tribal law enforcement," he said.

But soon after he made the comments, the Homeland Security Department declined to confirm that Clarke would join the department, and it has not made any official announcement about Clarke since.

A new Clarke controversy arose over the weekend when CNN's Andrew Kaczynski reported Saturday that the bombastic sheriff plagiarized at least 47 parts of his master's thesis in security studies from the Naval Postgraduate School in California. In each of those instances, Clarke appeared to list sources in his footnotes but did not use quotation marks around language that was lifted from the sources.

Clarke took aim at Kaczynski on Twitter, calling him a "hack" and a "sleaze bag."

In a radio interview that aired Monday, Clarke said the plagiarism allegations put his spot in the Trump administration up in the air.

"This is about weakening, like I said, the support that I give and that I have with President Donald Trump and Secretary Kelly, it's to weaken their resolve to hang in there with me," Clarke said. "Will it be successful? It might, but I'm not going to lose any sleep over that."

In a separate interview that aired Tuesday, Clarke admitted that he could have done a better job of formatting his work.

"Everything that I put in there had a citation and, naturally, when you accuse someone of plagiarism, it's not citing stuff," he said. "That's not even what CNN and their political hack Kaczynski said. They're saying certain words and phrases I should have put quotation marks around. OK, all right, fine. Maybe from a formatting standpoint the thesis isn't perfect, but the content is there."

Far outweighing the plagiarism allegations, however, are the deaths of four inmates at the Milwaukee County Jail, one of whom was an infant. Another death, due to dehydration, led to an inquest jury recommending charges against seven jail employees earlier this month. Clarke has mostly downplayed the deaths, blaming them on the inmates' health late last year.

Juliette Kayyem, who in the Obama administration held the position Clarke said he was to be appointed to, told Business Insider that Clarke's "history and conduct prove he should not be anywhere near a federal position representing the US."

"But even if you got past that, the idea that his job would be to coordinate with the vast array of partners that support our homeland efforts defies any logic," she continued. "He is not a uniter."

Gwen Moore. Alex Wong/Getty Images

When Clarke first made his comments about his upcoming appointment, Moore's office said it quickly became the second-biggest source of phone calls from constituents to her office, trailing just the American Health Care Act.

"That's why I was able to get 50 signatures in like 30 minutes," she said of the letter sent to Kelly on Wednesday.

Moore, who said she "was petrified and alarmed" when she first heard Clarke's comments last week, said she believes that Clarke's controversies are clearly being "taken into account" by DHS since they have refused to confirm whether he is being appointed to the job.

"I am assuming from their reluctance to finish the personnel process that my letter in addition to reporting about his writings and plagiarism, things are being taken into account," she said.

Making note of the deaths in Clarke's jail, Moore called the sheriff "such a mismatch" for the job description, adding that he "is not respected in many communities."

"I mean just look at how he treats his constituents," she said.

Natasha Bertrand contributed to this report.