Republican Warren Davidson was sworn into the House on Wednesday to take former House Speaker John Boehner's long-held seat, elected with the backing of the same conservatives who helped drive Boehner from Congress.

Davidson, 46, a former Army Ranger and businessman, became a cause celebre for conservative groups who craved the symbolic triumph of capturing Boehner's old district in southeastern Ohio.

Boehner served 25 years in Congress and became speaker after Republicans won House control in the 2010 elections. He quickly won the enmity of tea party conservatives elected that same year and outside conservative organizations, who said he was too willing to broker compromises with President Barack Obama.

In brief House floor remarks after taking the oath of office, Davidson suggested that lawmakers are well positioned to take a dominant role in their perennial struggle against the White House.

"The founders intended us to have a strong Congress," he said. "And especially with the presidential race the way it is, Congress truly has an opportunity to show real leadership."

Boehner, 66, abruptly resigned from Congress last fall amid efforts to pass budget legislation over the objections of conservatives.

Rep. Paul Ryan, R-Wis., succeeded him as speaker. He has so far had better relations with conservative Republicans, but at times found it difficult to win their support.

Davidson will serve the remaining seven months in Boehner's term and is the prohibitive favorite to be re-elected to a full two-year term this November.

A Boehner aide said the former speaker was in Ohio Thursday. In a statement, Boehner said his successor "can be counted on to continue the fight for a smaller, less costly, more accountable federal government."

Backed by television ads paid for by conservative groups, Davidson won a March primary over 14 GOP rivals. He then cruised to easy victory in Tuesday's special election over Democratic and Green Party rivals in the Republican-leaning district.

The conservative Club for Growth spent $1.1 million to support Davidson. The House Freedom Fund -- a political committee financed by hard-right lawmakers in the rebellious House Freedom Caucus -- contributed $43,000.

"We've got a conservative guy, a Freedom Caucus type of guy, who's now in Congress," caucus leader Rep. Jim Jordan, R-Ohio, said of Davidson. He said it "just so happened" to be Boehner's seat.

The Senate Conservatives Fund, which backed Davidson, praised him as "a principled conservative who won't cut deals with the Democrats."

Conservatives' expenditures overcame $250,000 by the Credit Union National Association and $281,000 by Defending Main Street, which backs mainstream conservative Republicans. Those groups supported Davidson's chief foe in the primary, state Rep. Tim Derickson.

Conservatives also spent heavily to help defeat Rep. Renee Ellmers, R-N.C., in a runoff primary this week. She lost to a fellow incumbent, Rep. George Holding, after new district lines forced the two colleagues to face each other. Ellmers had not previously represented most voters in the new district.

Ellmers is the only House GOP incumbent so far this year to lose a primary election, with mainstream GOP groups successfully fending off conservative challenges in Texas, Illinois, California and other states.

Republicans now have a 247-188 House majority. Democrats are expected to narrow that margin in November's election but fall short of the 30-seat gain they would need to win control.