"The bigamy statute appears to be nothing more than a thinly veiled attempt to 'use the power of the state to enforce [majority views regarding morality] on the whole society through the operation of criminal law' and as such cannot survive even minimal scrutiny," according to a motion to quash Nielsen's indictment filed this week.
In a separate argument, Nielsen's attorneys claimed the bigamy law is unfairly enforced and unconstitutional because it applies only to certain groups.
The law, for example, would not apply to three women living together who consider themselves married, or three men in the same situation, attorneys wrote, because marriage in Texas can only be between a man and a woman, and the bigamy statute requires that the accused is legally married to one person.
In a separate motion to limit Nielsen's potential sentence, his lawyers said that the state unfairly targeted the FLDS when the legislature strengthened its bigamy law in 2005, after the sect moved to the state and established the remote Yearning for Zion Ranch in Eldorado.
Four witnesses, including Utah Attorney General Mark Shurtleff and author Jon Krakauer, testified during those legislative hearings that the FLDS church is "a radical religious cult," according to the motion.
That testimony helped raise the bigamy statute from a class A misdemeanor to a third-degree felony for polygamous marriages not involving underage people an action that Nielsen's attorneys argue violated the constitutional separation between church and state.
If Nielsen is found guilty, his attorneys say he should be punished under class A misdemeanor sentencing by up to a year in jail and a fine of $4,000 or less, instead of third-degree felony guidelines of two to 10 years in prison and a $10,000 fine.
Nielsen served as president of the FLDS church after leader Warren Jeffs was sentenced on accomplice to rape charges in Utah. But he lost his position earlier this year when Jeffs took back the presidency of the FLDS church. Nielsen was one of dozens of men excommunicated by Jeffs this year.
He is one of 12 men, including Jeffs, who were charged with crimes related to bigamy and underage marriages following a massive raid on the YFZ Ranch. All eight men who have come to trial so far have pleaded no contest or have been found guilty. Jeffs was convicted on sexual assault of a child charges in August and is serving a life sentence in a Texas prison.
The bigamy law in Utah is also under attack from a very different polygamous family: the Browns, who were made famous by the reality show "Sister Wives." A Washington, D.C.-based constitutional law attorney announced the federal lawsuit in August, but the Utah Attorney General's Office argues that the Browns who have not been linked to underage marriage or other abuse do not have standing to challenge the law because they haven't been charged with any other crimes.