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WASHINGTON — Devin Nunes once said all he wanted to do was work on a dairy farm.

Now the man from the rural Central Valley of California is running one of the most scrutinized, complex and politically fraught congressional investigations in recent memory.

As chairman of the House intelligence committee, which holds its first public hearing on Monday, Nunes is at the helm of a probe of Moscow's meddling in the 2016 campaign and the murky web of contacts between President Donald Trump's campaign and Russia.

It's a potentially sprawling enterprise that spans continents, plumbs spycraft and dominates international headlines.

On Sunday, Nunes pushed back on the president's claims that the Obama administration had wiretapped the Trump building on Fifth Ave. in New York City.

"No, there was no FISA warrant that I’m aware of to tap Trump Tower," Nunes told Chris Wallace on Fox News Sunday, flexing his muscles as the head of his committee. The California representative added that they would still investigate the unmasking of former National Security Adviser Gen. Mike Flynn’s interactions with the Russian ambassador.

"We know a law has been broken and we need to get to the bottom of it," Nunes said to Wallace, noting that he had seen no evidence of collusion between Russia and the Trump campaign. "As it relates to the Russians, we are happy to investigate it because I think Putin is a bad actor on the world stage."

He's a long way from raising cattle.

"I'm not asking for any profile," Nunes told the Associated Press, when asked about his new place in the spotlight.

Until recently, the soft-spoken 43-year-old — dubbed a "normal dad" by friends — was hardly a fixture on the national news circuit. Now he is holding weekly press briefings and being asked to weigh in on daily twists and unexpected developments. At Monday's hearing he will call FBI Director James Comey as a witness, an event that amounts to must-see television in Washington.

Nunes was not an early Trump backer, but was named to the transition team as an adviser on appointments.

The burden of leading a bipartisan, credible investigation into the integrity of the U.S. campaigns, not to mention the possible role of the new president's campaign associates, is a heavy one not only for him but for many veteran lawmakers.

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On the other side of the aisle, Democratic Sen. Mark Warner, of Virginia, has said the Senate intelligence committee investigation, which he is co-leading, is probably the most important thing he will do in his public life. Nunes says he does not feel the same way.

"Everything we do around here is really important," Nunes said. "I wouldn't put one in front of the other."

It's an understatement his friends recognize.

Nunes is a third-generation Portuguese-American, and he grew up working on his family's dairy farm. As a teenager, he raised cattle and saved money to buy farmland with his brother, according to his congressional biography. He has degrees in agriculture and keeps his hand in farming through an investment in two California wineries run by a friend he met through his alumni network.

Rep. David Valadao, a Republican congressman from a district next to Nunes' and fellow dairyman, said Nunes takes his job as congressman seriously. But, he said, aside from his work, "he's a normal dad" to three young daughters.

"All I wanted to be was a dairy farmer," Nunes told a group of high school students as he campaigned for his seat in Congress in 2002, according to an article in the Fresno Bee.

His education and childhood aspiration suited his political ambitions. Like many politicians from California's interior farm belt, Nunes was well versed in agriculture and the water supply that supports it.

Nunes' first entree into politics was as a member of the board of a local community college. He ran for Congress in 1998 and lost in the primary. In 2001, he was appointed by President George W. Bush to a California post at the U.S. Department of Agriculture.

He was only 28 when he won a hotly contested congressional seat, beating his Republican competitors in the 2002 primary by appealing to the concerns of ranchers and dairymen in his solidly conservative district.

Tom Barcellos, a Tulare County dairy producer who has known Nunes since he was a child, said Nunes was focused early on politics, without being showy.

"He knew what he wanted and he did his research, and he didn't blow a lot of smoke," Barcellos said.

Nunes consistently has supported bills that would roll back environmental protections and boost federal water supplies to the fertile farmlands of the San Joaquin Valley, the lower stretch of California's vast Central Valley. His ongoing fight against what he describes as jobs-killing regulations promoted by "radical environmentalists" is a priority shared by a local group of wealthy farmers who belong to the giant Westlands Water District, which hired Nunes' friend and former chief of staff as its deputy general manager two years ago.

"Devin, from day one, has made water his top priority," said Tom Holyoke, a political scientist at California State University, Fresno.

Nunes served on the Agriculture Committee during his first term, but quickly landed a spot on the House Ways and Means Committee, one of Congress' most influential panels.

He was spotted by Republican leaders as a party loyalist and he was named to a leadership position during his first term.

He vied for the chairmanship of the intelligence committee in 2014. While competing against more senior members, he proved a better fundraiser, bringing in far more money for his party than his competitors for the chairmanship. While many congressional committee leadership positions are based on seniority, the House intelligence committee leadership was chosen by then-House Speaker John Boehner.

Nunes has suggested he pursued the intelligence committee post because it would be good for his constituents. Intelligence can play a key role in trade negotiations, he said, although it is only a sliver of the intelligence agencies' missions.

"The intelligence committee — that's a committee that I call the tip of the spear, because without national security it's tough to keep those trade routes open," Nunes said in a 2014 interview with the Tulare Advance-Register.

Until now, much of Nunes' work on the committee has been focused on investigations into NSA leaker Edward Snowden, the intelligence behind the Iran nuclear deal, Hillary Clinton's emails and the placement of a Defense Department intelligence center.

The congressman made a push to have the center built on the Azores islands, 800 miles off the coast of Portugal, a proposal that was popular among the valley's many dairy producers of Portuguese descent. The department ultimately chose a site in the U.K.

Monday's hearing will be the latest spotlight on the tension between Nunes' loyalty to Trump and his commitment to a thorough, bipartisan investigation.

The congressman's independence has already been questioned. Last month, the White House enlisted him to push back on a news article it didn't like about Trump associates' ties to Russia. The congressman has said he did nothing improper when he reached out to a reporter.

Nunes has not appeared to relish the role of Trump defender. He's described Trump as a "political neophyte." Asked about Trump's tweeted claims that former President Barack Obama wiretapped his phones, Nunes' response did little to help quiet the controversy.

"Are you going to take the tweets literally?" Nunes said. "If so, clearly the president was wrong."

Burke reported from San Francisco. Researcher Jennifer Farrar in New York contributed to this report.