Even after three strikes, advocates for a “progressive” income tax aren’t out. Their proposal to replace Colorado’s 4.4% flat income-tax rate with an array of tax brackets is once again moving ahead toward next November’s ballot after state officials gave it a green light last week.

The initiative had been derailed temporarily several times by challenges to its constitutionality before the state Initiative Title Setting Review Board. For now, the tax hike is back on track.

The details of the proposal vary across eight versions, each featuring one of two tax structures with six brackets ranging from 3.7% for incomes below $25,000 to 9.5% for those earning $1 million. Under a previous iteration, the tax hike would cost taxpayers $4.1 billion a year. Now, there’s a range. It all depends on which version the proponents decide to advance to next fall’s ballot. Then, the real work begins — gathering at least 125,000 voters’ signatures to get there.

Each version of the tax hike lets the legislature keep excess revenues above Taxpayer’s Bill of Rights caps on government growth — rendering future TABOR refunds exceedingly unlikely. In other words, the proposal not only would dig deeper into many Coloradans’ pockets; it also would gut TABOR — a watershed, voter-enacted safeguard for taxpayers.

Polls show TABOR remains overwhelmingly popular among Coloradans, and voters likely will be wary of any attempt to remove its protections.

They also may reason, wisely, that Colorado’s current flat tax ensures everyone pays their fair share. It requires the same proportion of everyone’s household income; the more you earn, the more you pay.

When the current income tax already nets over $17 billion annually, soaking the public for additional billions could turn out to be a tough sell.

Ironically, potential opposition to the pending proposal extends to one of our state’s most prominent and powerful Democrats. While Jared Polis is notoriously coy about where he stands on a lot of ballot issues, he has voiced support over the years for modest cuts implemented at the ballot box to the state’s flat tax. He’s unlikely to support a scheme that goes in the opposite direction. After all, Polis may identify as a progressive — but on this matter, he is a realist.

The whole debate presumes of course Colorado needs an income tax in the first place. Polis himself has advocated on several occasions for eliminating the state’s income tax entirely.

After all, an income tax penalizes productivity, i.e., hard work, and undermines prosperity. 

Any income tax also puts Colorado on the wrong side of states that don’t have one — like neighboring Wyoming, Nevada and the second-most-populous state, Texas. Having no income tax is a key draw in luring job-creating investment; raising the income tax, as a progressive tax would, stands to make our state even less competitive.

That has been the point pressed by Advance Colorado, the advocacy group that has gamely fought the progressive tax proposal all along and helped persuade the Title Board to rule against the pending tax hike on previous occasions.

In a recent press statement, Advance forewarned, “…the tax hike would chase jobs out of our state, hurt Coloradans and continue to push our revenue down.”

Fortunately, this isn’t the final word. Advance Colorado and taxpayer watchdog Natalie Menten are preparing another challenge before the title board on Feb. 4. Stay tuned.