Missouri voters passed a constitutional amendment asserting the right to pray.

Reiterating a protected right under the U.S. Constitution, on Tuesday Missouri voters overwhelmingly approved an amendment to the state constitution reiterating individuals' right to pray publicly and in schools.

On a day when GOP primaries promised the most competitive statewide races, it passed with 83 percent of the vote, with only two precincts still outstanding. The measure was introduced by Republican state Rep. Mike McGhee and moved onto the ballot by the General Assembly.

The amendment's official ballot title:

Shall the Missouri Constitution be amended to ensure:

• That the right of Missouri citizens to express their religious beliefs shall not be infringed;

• That school children have the right to pray and acknowledge God voluntarily in their schools; and

• That all public schools shall display the Bill of Rights of the United States Constitution

Freedom of speech and religion are already protected under the Bill of Rights, and critics of the bill called it unnecessary and a push to trample religious minorities. Republican lawmakers pursued the measure as a clarification of doubt.

Speaking to the St. Louis Post-Dispatch in May, Democratic state Rep. Mike Kelly criticized the amendment as "jobs bill for lawyers." The measure also drew opposition from the Islamic Foundation of St. Louis, which voiced fears that the bill sent a message of exclusion to religious minorities. Missouri's four Catholic bishops supported the amendment, the Post-Dispatch reported.

Religion's constitutional protections haven't kept school-prayer issues out of court, in cases that have riled Christian conservatives. Last spring, for instance, a federal judge barred students at a Texas high school from asking audience members to pray at a graduation ceremony, before the 5th Circuit Court of Appeals lifted the ban.

Get more pure politics at ABC News.com/Politics and a lighter take on the news at OTUSNews.com