FORT WORTH, Texas A Texas appeals court appeared hesitant on Tuesday to overturn the criminal conviction of Crystal Mason, a 44-year old woman sentenced to five years in prison for illegally voting in the 2016 election.

Mason cast a provisional ballot in 2016 while on supervised release for a federal felony related to inflating tax returns. Texas prohibits felons from voting while they are serving their sentences, but Mason says she had no idea she was ineligible to vote.

Election officials didnt count Masons ballot, but Tarrant County District Attorney Sharen Wilson (R) brought charges against her anyway and successfully convinced a lower court judge that Mason knew she was ineligible to vote and did so anyway. The state pointed to the fact that Mason signed a provisional affidavit warning her about voter eligibility to prove she knew she could vote.

Much of a brief oral argument Tuesday afternoon focused on the fact that Mason voted with a provisional ballot. Mason didnt actually vote because her ballot was rejected, Thomas Buser-Clancy, one of Masons attorneys, told the three-judge, all-Republican panel. Federal law requires election officials to offer people like Mason a chance to vote if they are uncertain about their eligibility, and its determined later whether their ballots should count. Thats exactly what happened in Masons case, Buser-Clancy argued, and by prosecuting her, Texas was essentially criminalizing a process protected by federal law.

Ms. Mason was convicted of illegal voting for following procedure set forth by the federal government to submit a provisional ballot, Buser-Clancy, an attorney with the Texas chapter of the American Civil Liberties Union, said during his oral argument. Ms. Mason did not vote on November 8, 2016. Ms. Mason submitted a provisional ballot and that ballot was rejected. That is not a vote in an election.

Justice Dabney Bassel noted the states illegal voting statute requires that the person know they are ineligible while voting to commit a crime. He pressed Buser-Clancy on whether prosecuting a person who knowingly votes illegally is incompatible with federal law that requires provisional ballots for people unsure about their status.

Justice Elizabeth Kerr seemed interested in whether casting a provisional ballot could be construed as an attempt to vote. But Masons lawyer Buser-Clancy and Helena Faulkner, who represented the state of Texas, noted that Mason was not charged with attempting to vote; she was charged with actually voting.

Masons case immediately drew national attention last year because her sentence was so severe. Masons lawyers say her case is an obvious attempt to scare minority voters and people with criminal histories away from the ballot box.