Dixon is the charming little city, a hundred miles west of Chicago, where President Ronald Reagan grew up.

But it’s better known these days for what may be the largest municipal rip-off in American history: Rita Crundwell’s theft of nearly 54 million tax dollars, over 20 years as Dixon’s treasurer and comptroller, to support her horse breeding business and lavish jet-set lifestyle.

How did she get away with it? Simple: No other city official was checking on her handling of tax dollars, and Dixon’s outside auditors and accountants were asleep at the wheel.

In fact, alarm bells didn’t go off until 2012, when the city clerk, filling in while Crundwell was on vacation, discovered a checking account with the unmistakable scent of fiscal fraud, and told the mayor, who alerted the FBI.

Since then, Crundwell’s gone to prison, Dixon’s recovered most of the money by settling lawsuits against the negligent accountants and auditors, and—hopefully— Illinois residents have gotten the message: Public officials have to be closely monitored by watchdogs trained to expose and help eliminate corruption.

Investigative reporters and groups like the Better Government Association watch from the outside, but someone—preferably an independent inspector general with broad powers— should be watching from the inside.

The biggest units of city, county and state government have IGs, and their impact varies widely, as BGA investigations have revealed.

The best IGs can reduce some of the bad behavior, identify blind spots that impede fraud prevention, conduct audits that flag inefficiencies and assess the quality of government services, uncover conflicts of interest that erode public trust, and scout out best practices in other jurisdictions.

At the very least, the presence of an IG can serve as a deterrent.

Unfortunately, too many units of government have no internal watchdog.

Suburban Cook County is a glaring example— a patchwork of 130-plus cities, towns and villages that collectively rival Chicago in their politics, population and the billions of tax dollars they collect and spend.

But with the exception of a few financially strapped municipalities that have accepted County Sheriff Tom Dart’s offer to serve as their IG, hardly anyone is watching suburbs that collectively spend 5 billion tax dollars a year, and employ nearly 25,000 people.

We’ve conducted numerous investigations of suburban mischief, including waste, fraud, inefficiency, nepotism, cronyism, patronage, conflicts of interest, pay-to-pay, and embezzlement—the administrator of a school treasurer’s office we drilled down into was recently sentenced to nine years in jail for stealing hundreds of thousands of dollars.

An obvious conclusion: It’s time for the Cook County Board to seriously consider empowering Sheriff Dart to investigate misconduct allegations in every suburban community that doesn’t have an internal watchdog of its own.

County President Toni Preckwinkle apparently opposes the idea, so maybe she can tell us why, or suggest another oversight strategy.

State lawmakers are also looking at ways to equip every Illinois municipality with a watchdog, so let’s see where that goes.

But let’s not wait until we’re blindsided by another Dixon-like scandal.

Dixon learned its painful lesson the hard way, and since then they’ve implemented internal controls to follow the money.

Taxpayers in suburban Cook and elsewhere deserve the same protection from the mice that play when the cat’s away.

Andy Shaw is President & CEO of the Better Government Association. He can be reached at ashaw@bettergov.org. Find him on Twitter @andyshawbga