There are two broad schools of thought on political critics, or rather two that can be described here using largely polite terms.

The first comes by way of the American founding father Benjamin Franklin: "Critics are our friends, they show us our faults." The second is exemplified by the thoughts of Plutarch, the Greek historian and essayist: "It is a thing of no great difficulty to raise objections against another man's oration, it is a very easy matter; but to produce a better in its place is a work extremely troublesome." And it's into one of these two boxes that the words of David Clarke Jr., Sheriff of Milwaukee County, Wis., will fall for many Republican National Convention viewers tonight.

Technically a Democrat, Clarke took the stage during prime time hours. Why? Well, it probably has about as much to do with who Clarke is as it does what Clarke will say.

The son of a former Army Ranger and Korean War vet, Clarke began his own law enforcement career in the late 1970s, according to a 2003 profile written about Clarke in Milwaukee magazine. He was just 21 years old. Described by his father as a boy always disciplined and well-behaved, police work was a good fit. Clark, his father said, always seemed respect authority in any setting. He rose through the Milwaukee Police Department ranks, becoming a detective, a homicide investigator and then a police captain inside of 25 years.

Clarke was making plans -- literally-- to take the helm of the department when the county's sheriff announced plans to leave office before the end of his term. Wisconsin's Republican governor, at the time Scott McCallum, decided to appoint Clarke to the job. And soon, Clarke became a kind of Milwaukee attraction, one of those elected officials able to draw large crowds, appeal to people across party lines and say things that no white politician, certainly no white Republican would without some kind of blowback in the very politically blue, nearly 1/3 black Milwaukee area. Plus, Clarke was 6'4" tall and equipped with "GQ good looks," according to that 2003 profile.

Donald Trump souvenir buttons are seen on the first day of the Republican National Convention on July 18, 2016, in Cleveland, Ohio. Thousands of delegates descended on a tightly secured Cleveland arena Monday for the opening of the Republican National Convention, with Donald Trump's wife playing character witness as the tough-talking mogul locks up his party's presidential nomination. (DOMINICK REUTER/AFP/Getty Images)

So Clarke was relatively young, attractive and also an experienced law enforcement official, with the kind of resume and personal assets that rarely do a male politician harm. He was a prominent public figure in a community struggling with poverty, unemployment and crime for a good portion of the last 20 years and, some might argue, a collection of entrenched power brokers unwilling to surrender their fiefdoms and public funding in the interest of trying new things. In Clarke, conservatives not only found a voice saying exactly what they think or want to advance for political purposes coming out of a politically unexpected body, said Juliet Hooker, a political scientist at the University of Texas-Austin and the author of the 2009 book, Race and the Politics of Solidarity.

Here's what Hooker told the Fix about Clarke's rise to the Republican Convention stage via a brief email exchange. Hooker was traveling Monday and unable to engage in an extended interview.

The appeal of a black conservative like Clarke is that their views disrupt what I call racialized solidarity...(i.e. that blacks and whites tend to have different views of the same events, as has been largely true of Black Lives Matter even with all the videos showing police escalation, culpability, etc.).

This  allows the critique of BLM [Black Lives Matter ] to become an issue that Republicans can say is about  ideology, not racism. Clarke himself does this when he talks about liberals not being willing to call them a hate group, etc.

This narrative also fits in with the Republican base's feeling that racism against whites is a problem that is not being acknowledged and that is stronger than anti-black racism.

In the United States race continues to shape almost every aspect of daily life. That includes but is not limited to where they live, where they work, how much they earn, what they have in the bank, the quality of their children's schools and the health care they receive, the proximity of parks, pools, libraries, public transportation and other life-enriching public services and conveniences as well as how often they encounter police and what happens when they do. So, much to the chagrin of many a conservative commentator who bemoans the continued existence of identity politics, there are real reasons why identity also continues to shape most Americans' sense of their primary political needs.

Some individuals reject that. And that's a role that Clarke has embraced. He's made a series of public statements that really -- in their content and tone -- amount to cover fire making it easier for conservatives to challenge the very decency of challenging or questioning the police, no matter the death toll of some police tactics or how disproportionately they affect black and Latino families. On Monday Clark doubled down on that work beginning his speech with a declaration that blue lives matter and going on to describe any critique of police as utterly wrong at any time.

In recent weeks leading up to the convention, Clarke has placed blame for attacks on police officers in Dallas and Baton Rouge, La., squarely on organized and semi-organized efforts to protest racial disparities in policing and deaths while in contact with police. Clarke has called Black Lives Matter  "domestic hate group," group which spouts "hate-filled messages," and encourages or even produces violence wherever it goes. He's also challenged the Southern Poverty Law Center, an organization that studies and tracks hate groups, to label Black Lives Matter according to Clarke's description or lose all credibility, Clarke says.

There's no evidence to support what Clarke has said. More than one Black Lives Matter activist has publicly condemned the police murders in Dallas and Baton Rouge. But that is what Clarke has said, nonetheless. In doing so, he's taken on two of the biggest baddest modern conservative political bogymen in one fell swoop. He expressed a set of ideas that in the context of this particular convention will allow Trump and the party set to make Trump its presidential nominee to lay claim to a law and order position, strongly imply that the opposition does not agree.  Then, in a particularly shrewd act of modern politicking, attempt to dismiss claims that these fact-free standard Republican arguments reflect some kind of bigotry. They can't be biased ideas -- this logic goes -- because they come from a black man who is also a law enforcement official.