It was no small feat that House Republicans stood their ground against a progressive income tax in April.

That move – with 50 members signing on to a resolution opposing a progressive tax – denied House Speaker Mike Madigan the votes needed to push a constitutional amendment on November ballots. The speaker responded in kind, filing a resolution of his own supporting a progressive income tax in Illinois.

That’s when taxpayers saw an even bigger win.

The same day Madigan filed his resolution, downstate Rep. Jerry Costello, D-Smithton, not only lent his voice to the chorus criticizing a progressive tax, he signed on as chief co-sponsor for a resolution denouncing the idea. Costello stuck his neck out on behalf of his constituents on this issue despite Madigan’s move.

Taxpayers should be heartened that with a little elbow grease, change is possible. Around 30,000 Illinoisans have signed a petition opposing the progressive tax on illinoispolicy.org. That type of grassroots support can be enough for lawmakers to take risks on a tax issue.

But some clearly remain unmoved, such as state Rep. Michelle Mussman, D-Schaumburg.

When confronted at the Statehouse with nearly 1,000 signatures from residents in her district opposing a progressive tax, the lawmaker was unenthused.

“No change in my public position,” she said. “Tell your activists they can keep doing this, but I won’t participate.”

“Activists” is an interesting way to describe constituents.

Scrapping Illinois’ constitutional protection of its flat income tax would remove the most significant safeguard against tax hikes for families and businesses. Making all Illinoisans pay more – as state lawmakers did last summer – is a tougher sell than tinkering with different rates for segregated income groups. You can also raise taxes on one group now and another group later – and won’t need to deal with nearly as many angry phone calls and emails.

J.B. Pritzker has made a progressive income tax a cornerstone of his campaign. The Democratic gubernatorial candidate has used the device as somewhat of a cure-all, claiming it could pay for things like universal preschool, more funding for higher education, lowering property taxes, paying down the bill backlog and more.

Just in time for Pritzker’s general election run, the union-backed Center for Tax and Budget Accountability released a report claiming a progressive tax could mean a tax cut for a whopping 98 percent of Illinoisans. And not only that, the progressive tax would also reduce the deficit and spur economic growth.

But Springfield history and an economic review of all 50 states flies in the face of these claims.

First, some of the same lawmakers promising tax cuts under a progressive tax structure also promised the 2011 tax hikes would be temporary. Yet, three years after their expiration, they were made permanent. Promises are made and broken often at the Statehouse. Progressive tax proponents would have Illinoisans trade their flat-tax protection for a political promise that isn’t worth the paper it’s written on.

Second, data from the Bureau of Economic Analysis provides a window into the results of states with a progressive income tax.

From 2006-2016, states with a progressive income tax saw their economies grow slower than states without a progressive income tax. They also saw employment grow slower.

What about inequality? Many progressive tax advocates cite inequality as a major motivation for reform. Well, states with progressive income taxes see higher inequality, and they have seen inequality grow faster than states without a progressive income tax over the past decade.

Is a weaker economy fair? Is weaker jobs growth fair? Is greater inequality fair?

Of course not. But a progressive income tax isn’t really about fairness. It’s just the next idea in a long line of failed policies hoping to pay for spending levels Illinoisans can’t afford.