– Attorney General Chris Koster cautiously weighed in with support for Gov. Jay Nixon’s position on at least part of the controversial tax cut bill his fellow Democrats are fighting to prevent from becoming law.

In a letter sent on Thursday at the request of House Speaker Tim Jones, a Republican, Koster – a likely Democratic candidate for governor in 2016 – said Nixon is right in saying that House Bill 253 does include a retroactive tax cut which could cost the state millions.

“In the opinion of this Office, the plain language of the new legislation suggests that, if certain triggering events set forth in the statute occur, taxpayers may seek refund of taxes paid in the three preceding tax years,” he wrote. “If the General Assembly did not intend that taxpayers should get any benefit from the backward-looking change, why include that language?”

Koster said it was his opinion that the “prohibition against the retrospective application of laws” would not pose a barrier for taxpayers seeking refunds under the General Assembly’s bill.

In a statement, Jones said Koster was acting with political motivations, not legal ones.

“I am disappointed that Attorney General Koster chose not to show his independence on this important issue and instead sided with the liberal, tax-and-spend views of the governor and the president. In doing so, he missed an opportunity to join Republicans in our defense of Missouri taxpayers,” Jones said. “Going forward, we will continue to rely on the legal analysis of our independent, non-partisan Legislative Research department that clearly refutes the highly-partisan claims made by the governor and now the Attorney General.”

While Koster’s argument supports Nixon’s position on the bill, Koster — who has taken some $300,000 in campaign funds from Rex Sinquefield, the St. Louis billionaire bankrolling much of the override effort — has not explicitly taken a position on the bill.

Nixon has campaigned across the state claiming a significant hit to the state’s coffers that could harm funding for education if his veto is overturned in September.

Read the full opinion here.