Amazon is closing its affiliate program in Illinois, a day after the governor signed a law requiring Amazon and other online retailers to collect sales taxes on goods sold in the state.

It follows moves Amazon has made in other states that have cracked down on internet sales tax collections.

Up next: Vermont. The state House there on Thursday passed a bill to more vigorously go after taxes from online retailers. Vermont estimates the tiny state could get $25 million in new revenue from the uncollected sales taxes, according to a Bennington Banner post.

In a statement published on the chicagoist.com website, Amazon says the Illinois law is illegal:

“We had opposed this new tax law because it is unconstitutional and counterproductive. We deeply regret that its enactment forces this action.”

Earlier this week, Sears sought to sign up disgruntled or jettisoned Amazon sales affiliates doing business in Illinois.

Amazon’s protracted battle with states over sales taxes has caught fire in recent months, with states strapped for cash and becoming more aggressive about finding new revenue sources. I have to wonder how long Amazon can withstand what could turn out to be an avalanche of states lining up against the online retailer on this issue.