ST. PAUL, Minn. (AP) — Top Minnesota lawmakers have approved an $18,000 legal expense in a fight to preserve a constitutional amendment that would require voters to show a photo ID at the polls.

The expense was approved Thursday on a divided voice vote by the Republican-led panel of senior House and Senate members. The taxpayer money will go to a private law firm that will seek to intervene in a lawsuit on the Legislature’s behalf.

A lawsuit filed weeks ago contends that the language of the November ballot question doesn’t accurately describe what the amendment would do. Plaintiffs argue passage of the amendment could weaken their voting rights. Supporters of the amendment say it’s meant to protect voter fraud.

The Minnesota Supreme Court is scheduled to hear the case on July 17.