File: Rep. David Brat (R-Va.) (Courtesy of Laura Brat)

Rep. Dave Brat (R-Va.) doesn’t plan to support Rep. John A. Boehner’s reelection as House speaker in the new Congress, a sign that the new lawmaker, who defeated then-House Majority Leader Eric Cantor in a primary last year, is positioning himself in the most conservative wing of the Republican Party.

“While I like Speaker Boehner personally, he will not have my support,” Brat said in a statement Monday. He argued that party leaders should have worked with conservatives to defund President Obama’s executive action granting legal status to millions of undocumented immigrants.

Immigration policy played a large role in Brat’s surprising victory over Cantor. Voters in his conservative Richmond-area district revolted after the influential congressman suggested comprehensive reform should be considered.

Because Cantor resigned before the end of his term, Brat, a college economics professor, was sworn in as a member of Congress last fall. The new lawmaker then supported Boehner (R-Ohio) during a closed-door leadership meeting, saying there was no alternative.

“I said I’d favor the person who most closely followed [my] principles, so no challenger emerged, so I followed my logic,” he told The Washington Post .

At least two conservative Republicans are planning to take on the speaker: Louie Gohmert of Texas and Ted Yoho of Florida. Both take a hard line on immigration. But Brat did not announce support for either challenger, saying only that he wants a speaker who will stand up to Obama.

The spending bill passed at the end of the last Congress “did nothing to reduce spending or work toward balancing the budget,” Brat said, and did nothing to block the Affordable Care Act or Environmental Protection Agency regulations. Leaders kept the bill “from members of Congress and the public until the last minute,” he said, giving them no time to read through the $1.1 trillion spending measure , which funds the government through September.

Several lawmakers have announced that they will not back Boehner in this week’s leadership vote. But the party’s success in the midterm elections makes an upset less likely, because the speaker has a larger caucus to court. Boehner’s opponents need 29 votes to deny him a majority of the caucus and force a second round of voting on the speaker’s position.

Twelve Republicans voted against Boehner’s leadership in 2013, a small rebellion fueled by dissatisfaction over bipartisan compromises. Three of the defectors voted for Cantor, who at the time was seen as a more steadfast conservative.