Springfield personal-injury attorney and medical doctor Brad Bradshaw has been slapped with a federal tax lien by the Internal Revenue Service, 11 months after his unsuccessful campaign to convince Missouri voters to back medical marijuana Amendment 3.

A lien for more than $701,000 was imposed on Bradshaw and his wife as of Sept. 19, according to IRS data collected by the Springfield Business Journal and posted Sept. 27. A tax lien is a legal claim by the government on assets held by a noncompliant taxpayer.

During the 2018 election cycle, the Associated Press reported that in 2017 and 2018, Bradshaw and his company already contended with two tax liens totaling $119,000.

Meanwhile, the Amendment 3 campaign committee, funded almost completely by Bradshaw, holds more than $2.1 million in debt, according to its most recent quarterly report with the Missouri Ethics Commission.

The Amendment 3 proposal was one of three medical marijuana ballot initiatives vying for voters' favor in the November 2018 general election. It would have set up a 15-percent marijuana sales tax to fund an independent cancer research institute. Bradshaw would have served as its leader on an unpaid volunteer basis.

Had the proposal passed, Bradshaw would have been constitutionally empowered to select the first nine members of the institute's board of directors, with no set time limit for his departure.

But after a fierce competition — including a pair of lawsuits Bradshaw filed seeking to kick the other two marijuana proposals off the ballot, and the formation of an anti-Amendment 3 group called Patients Against Bradshaw Amendment — voters ultimately went with Amendment 2.

A review of public campaign finance records from the 2018 election cycle shows that the Amendment 3 committee, Find the Cures, only gained traction with a handful of donors after its inception in 2015.

As the campaign progressed, Bradshaw regularly loaned money to the committee. Between Oct. 1, 2018, and the election, for example, Bradshaw extended seven loans, including one for more than $200,000, repeating a pattern that stretched back for years.

Reached Friday, Bradshaw told the News-Leader he takes responsibility for the results of the Amendment 3 campaign — fought while his own father was dying of terminal cancer — and that for him, the campaign reflected his passion in the fight against the disease.

"I had hoped that we'd build a world-class cancer research center in Missouri, and that's what Amendment 3 was about," he said.

Bradshaw took exception to critics' claims that the Amendment 3 campaign was essentially a vanity project.

"It got spun the way you mentioned because there were big interest groups that wanted the money (generated by a marijuana industry) for themselves, and not for a cancer-research amendment," he said.

Before the election, researchers predicted Missouri medical marijuana sales could top $100 million per year. Since the election, state officials have approved about 1,000 patients per week for qualifying marijuana patient or caregiver cards since they began taking applications in late June, and a system of 192 privately owned licensed dispensaries is in the works to come online in mid-2020.

Bradshaw said he believed the tax-funded institute proposed by Amendment 3 would have found effective cancer cures. (The amendment provided for making those available to state residents at no cost.)

"Nobody had the knowledge and the background to get this accomplished the way I did," he said.

Bradshaw referred questions about the tax liens to attorney Robert Fedor, a tax lawyer with offices in Chicago and Cleveland. The News-Leader was unable to reach Fedor, whose office said he was traveling out of state on Friday.

More on Missouri and cannabis:

Everything you need to know about medical marijuana in Missouri

Missouri Highway Patrol investigating 'Cannabus' traveling marijuana clinic

How to get a medical marijuana card in Missouri