There's a really eye opening report 2 years ago from Charles Rettig, commissioner of the IRS, where he openly states that his agency focuses audits on poorer people, because they have less resources to fight and are more likely to just pay up and move on. Most of the audit resources are targeted at people claiming the earned income tax credit.
https://www.propublica.org/article/irs-sorry-but-its-just-ea...
When our current President subscribes to using tax law shenanigans to avoid paying taxes you can damn well bet much of the rest of Congress and high ranking state leaders will be found doing the same. One of the larger avenues of abuse is through S Corporations which let individuals shunt off income thereby avoiding certain types of taxes. It is also used by leadership of various charitable organizations to redirect money for purposes many would think fraudulent; like using them to buy homes for use by organization leadership or cover business jet ownership