Juliette Kayyem, a former assistant secretary at the Department of Homeland Security, is the author of “Security Mom: An Unclassified Guide to Protecting Our Homeland and Your Home.”

Sheriff David Clarke speaks at the Republican National Convention in Cleveland on July 18, 2016. (J. Scott Applewhite/Associated Press)

If controversial Milwaukee County Sheriff David Clarke is correct, he’s being tapped for a senior role at the Department of Homeland Security. Although DHS hasn’t yet confirmed it, in a radio interview Wednesday, Clarke said he was “honored and humbled to be appointed” to the position, reportedly assistant secretary in the Office of Partnership and Engagement.

That’s my old job.

I’ve never met Clarke, but based on his inflammatory rhetoric, along with the cloud hanging over his tenure in Milwaukee, I’ll just come right out and say it: He’s not fit to serve at the agency tasked with domestic security for all Americans.

Last year, after four deaths at jails Clarke oversees, Milwaukee County auditors initiated an investigation into inmate medical treatment practices. Earlier this year, Clarke was accused of engaging in a hostile exchange with a fellow passenger on a commercial flight. He once likened President Barack Obama to Adolf Hitler, tweeting, “Hitler united all police forces under one commander. Obama trying to do the same using DOJ to federalize local police.” He conflated the Black Lives Matter movement with the Islamic State, tweeting, “Before long, Black Lies Matter will join forces with ISIS.” And he tweeted, “It’s incredible that our institutions of gov, WH, Congress, DOJ, and big media are corrupt & all we do is bitch. Pitchforks and torches time”.

None of this matches up with the work at DHS.

I served in the Obama administration as assistant secretary of Homeland Security for Intergovernmental Affairs. The title’s unwieldy, and not very descriptive, which might explain why the position is now labeled under the department’s Office of Public Engagement. The job’s remit, and mandate, though, is the same.

[If you work for Trump, it’s time to quit]

The team in the small Office of Public Engagement is focused on stakeholder engagement across diverse, complex and interconnected state, local, tribal and territorial law enforcement entities. That includes a big-city police chief who still called me “kid” (I’m 47) while asking for a $30 million grant, and a blue-state governor who asked whether the priority distribution of H1N1 vaccine to “political leadership” in each state extended to his wife and children.

The homeland is beautifully, challengingly complicated. In our system, DHS offers its limited tools to help jurisdictions guide safety and security planning, but a good deal of the work of my former office requires dialogue, empathy, patience and outside-the-box thinking to harness the capacity of these governmental entities, which have priorities that often, but not always, match with federal priorities. When communities face the worst, they expect local, state and federal efforts to combine to help provide homeland security for their citizens, whether it’s from the Coast Guard, TSA, FEMA, Secret Service, border enforcement or coordination with state and local police and sheriffs — all of which falls within Homeland Security’s charge.

With this as its undertaking, the department, and Homeland Security Secretary John Kelly, would be ill-served by a political antagonist such as Clarke. Going out of his way to inflame tensions between law enforcement and activists, stoking partisan fights and suggesting that the government and the people it serves are at odds all run directly counter to the approach this job requires. After the BP oil spill, when I was dispatched by a Democratic president to bring together five Republican governors to direct relief to the devasted gulf region, I knew that the citizens impacted didn’t care about ideology or party affiliation. I’m not sure Clarke does.

Yes, the department’s agenda has shifted under President Trump. I have fundamental disagreements with Kelly’s focus on draconian enforcement efforts against undocumented immigrants that needlessly divide communities and raise the ire of police departments that view immigrant outreach as a key to public safety. Under Attorney General Jeff Sessions, the Justice Department — once a target for Clarke’s brickbats — has signaled a war against mayors of sanctuary cities. The president’s travel ban, challenged by federal judge after federal judge, risks alienating Arab and Muslim communities, the very communities we need to help address potential homegrown threats.

[Trump’s administration says its travel ban isn’t like Japanese internment. It is.]

Nevertheless, I remain a member of the secretary’s Homeland Security Advisory Committee. I was appointed by the previous secretary, Jeh Johnson, to a multiyear term until it ends this summer. And I accepted that role because, despite my misgivings about the current administration, I believe that what unified us at DHS, and what unifies our homeland, cuts across party lines.

Core to that mission is bridging those disagreements and embracing our diversity. Sheriff Clarke shouldn’t be anywhere near that mission.