ST. LOUIS — The Lutheran Church-Missouri Synod recently carried out what various members consider the equivalent of a modern-day heresy trial.

The Kirkwood, Mo.-based church has 2.3 million members. The case pits two-term synod President Matthew Harrison — who is known for his bushy mustache and conservative views — against Matthew Becker, an outspoken pastor.

Becker is a theology professor at Valparaiso University, an independent Lutheran institution in Valparaiso, Ind., about an hour’s drive from Chicago. Becker has raised questions about the church’s stance against the ordination of women, as well as its teaching of creationism, or the literal reading of the biblical book of Genesis.

Becker’s insistence on talking about such issues has led certain members of the church to file charges against him to the synod, triggering several investigations.

To the disappointment of some, including Harrison, church panels handling the investigations have consistently cleared Becker, allowing him to remain in the church.

Yet, Becker, 52, was officially ousted last week, suddenly no longer a member of the church in which he was raised, though he remains on faculty at Valparaiso University.

“I happen to be right now the most infamous person in the synod,” Becker said recently, while noting the long lineage of family members active in the Lutheran Church-Missouri Synod, including his grandfather.

Becker’s ouster has led some to raise questions about the direction of the church, as well as leaders such as Harrison, who is up for re-election next summer.

Critics say the synod’s rules allow Becker to remain in the church but that pressure from certain leaders, including Harrison, ultimately sealed his fate.

Although Harrison could not be reached for comment, he has spoken publicly about Becker, including on a widely circulated Facebook post.

“I am saying that if my synod does not change its inability to call such a person to repentance and remove such a teacher where there is no repentance, then we are liars and our confession is meaningless,” Harrison wrote in January.

“I do not want to belong to such a synod, much less lead it. I have no intention of walking away from my vocation. I shall rather use it and, by the grace of God, use all the energy I have to call this synod to fidelity to correct this situation.”

While many agreed with Harrison, others argued that as a member Becker had the right to question the church.

“That’s what makes this so scary. We’re not even following our own system,” said Robert Hartwell, senior pastor at Village Lutheran Church in Bronxville, N.Y., intimating Harrison had overstepped his bounds.

Referring to issues such as women’s ordination, Hartwell said, “It seems now we can’t even talk about it.”

More moderate members of the Lutheran Church-Missouri Synod have clashed with conservatives before. In 1974, conservative Lutherans accused John Tietjen, then president of Concordia Seminary, St. Louis — an institution that trains future synod leaders — of failing to insist on a literal instruction of the Bible, especially the Old Testament. The controversy led the majority of Concordia’s faculty and students to walk out of the school in protest. Many eventually formed Seminex, a “seminary in exile,” at St. Louis University and Eden Theological Seminary. Seminex has since disbanded.

Tietjen helped organize in 1976 the Association of Evangelical Lutheran Churches, a collection of congregations that opted to leave the Missouri Synod.

As a leader of the group, Tietjen helped merge it in 1987 with the Lutheran Church in America and the American Lutheran Church. That merger created the Evangelical Lutheran Church in America, the largest Lutheran denomination in the U.S.

Some argue the 1970s schism left the church bereft of more moderate members, setting the stage for leaders such as Harrison. In a surprise defeat of a more liberal three-term incumbent — the Rev. Gerald Kieschnick — delegates of the denomination elected Harrison president in 2010.

Harrison’s victory represented a conservative ideological shift for the denomination, which has come with its set of challenges.

In 2013, for example, Harrison made headlines when in the wake of the tragic shooting at Sandy Hook Elementary School in Newtown, Conn., he asked a church pastor to apologize for participating in an interfaith vigil.

The church’s constitution prohibits members from taking part in worship services that blend the beliefs and practices of Lutherans with those of other faiths and Christian denominations.

The prohibition on worshipping with other Christians stems from the synod’s 19th-century history in Germany, when its members were forced by the government to accept Calvinism against their will — and fled to the United States to preserve their religious freedom.

More recently, members have questioned Harrison’s treatment of Becker. In February, numerous pastors and members signed an open letter, noting that, with regard to Becker, they were “extremely offended by the actions of President Harrison.”

Becker grew up in the Lutheran Church-Missouri Synod in Oregon. Because of some of his more liberal views, Becker had doubts about remaining in the church. Still, he hoped that as a member he could help reform the synod.

But by the late ’90s, Becker was attracting attention by publicly speaking about the ordination of women.

“There’s nothing in Scripture that clearly prohibits women from serving,” Becker said. “You don’t need a certain body part to share the love of God.”

In a blog post, Becker went even further, comparing the exclusion of women leaders from the church to “the institution of slavery and the subordination of people of color to whites.”

Becker has endured years-long investigations as a result. Then in April, the Rev. Terry Forke, a district president in Montana, filed a charge against him for failing to maintain that Genesis represents a historical record.

Soon after, Paul Linnemann, a district president in the northwest, asked Becker to resign.

“I feel like many people who are my opponents are making an idol out of the LCMS,” Becker said. “It’s almost as if the church cannot make mistakes.

“I’ve always taken the view that nothing should be off the table,” Becker said. He believes stifling discussion weakens the church.

Others, however, argue that Becker and the Lutheran Church-Missouri Synod are better off parting ways.

“It really doesn’t make sense for him to continue in our synod at this point,” said Eric Andersen, a pastor in suburban Chicago and associate editor of the conservative Lutheran blog The Brothers of John the Steadfast.

“He doesn’t believe what we believe, so it’s best not to pretend.”

Becker, for his part, argues the church “is not defined by Harrison and his narrow party views.”