The House GOP Steering Committee late Tuesday selected the longtime HASC member to succeed Rep. Buck McKeon, when the California Republican retires next month. The full Republican caucus is expected to sign off Wednesday.
Thornberry is the committee's current vice chairman, and his ascension to the top spot has been considered a done deal since McKeon announced his retirement in January.
One defense lobbyist with ties to House Republicans says Thornberry will look to put his own stamp on the committee's agenda.
"He's really going to sink his teeth in. He has served on the intelligence committee, and is passionate on Intel issues and C4ISR issues," the lobbyist said. "Thornberry will very much be engaged on issues across the board.
"And that's not a knock on McKeon. He was a great chairman and advocate," the lobbyist added. "Thornberry has had a vision for a long time about what he wants this committee to do. Remember he ran for chairman last time."
The lobbyist also believes Thornberry's relationship with Ranking Member Adam Smith,D-Wash., will be a plus for the panel.
Other analysts expect the House committee will continue on a path similar to McKeon's four-year agenda.
Benjamin Freeman, a defense budget expert at Washington's Third Way think tank, said he doesn't "think Thornberry will be a big change from McKeon."
"They're both defense hawks but, unfortunately, they've done little to rein in wasteful spending at the Department of Defense," Freeman said. "Hopefully I'm wrong, but we just haven't seen the Republican-controlled HASC make the hard choices our military needs to manage the post-Afghanistan drawdown."
Republicans counter such claims by saying GOP hawks — and pro-military Democratic members — have been right in blocking weapons-program cuts the Pentagon has proposed in order to cope with the automatic cuts.
"Instead of incentivizing reforms to mandatory spending, as its architects intended, the sequester became a bitter pill that fiscal hawks and the president were willing to swallow," Roger Zakheim, a former senior HASC aide, wrote in a Tuesday National Review piece.
"Ongoing operations against the Islamic State and ebola are only the most recent examples of how we continue to widen the gap between what we ask the military to do and what we provide them to do it," Zakheim wrote.
Thornberry became something a go-to guy for McKeon since McKeon took the gavel in 2011.
When McKeon wanted a subcommittee to focus on military intelligence issues, Thornberry chaired it. And when when McKeon decided to launch a major review of the Defense Department's weapons development and buying system, Thornberry again got the call.
With the acquisition review wrapping up soon, aides say it likely will influence the 2016 National Defense Authorization Act (NDAA), which will be Thornberry's first as the likely chairman.
Thornberry's expected tenure atop the panel means two southwestern Republicans will head the military oversight committees in the 114th Congress. Sen. John McCain, R-Ariz, is a virtual lock to take the upper chamber's Armed Services gavel in January.
Thornberry's move up is regarded as good news for the Pentagon and defense industry.
The Center for Responsive Politics, which tracks political donations, puts Lockheed Martin and Northrop Grumman has the top donors to his successful 2014 re-election campaign.
Lockheed donated $75,900 during the 2013-2014 election cycle. The defense giant builds the F-35 fighter, a crucial program for the company, in the Lone Star State.
Northrop gave his campaign $29,000, with the defense sector giving a total of $162,200. Another category of donors, which the center calls "miscellaneous defense" donated another $82,750 to Thornberry.
Other defense firms dot Thornberry's top 10 donors, including shipbuilding Huntington Ingalls, General Dynamics and Raytheon.
With Republicans soon to be in control of both chambers, GOP members already are making noise about shrinking or voiding the Defense Department's portion of pending sequestration cuts.
"I am very confident that the Armed Services Committee, under the leadership of John McCain next year, that we're going to make some corrections [to] sequestration," Georgia Sen. Saxby Chambliss told reporters last week.
Much has been written since the tea party wave of 2010 about whether or not the old-school Republican defense hawks have lost their collective congressional clout.
With Thornberry and McCain taking over the Armed Services panels, Zakheim contends, we are about to find out.
"Come January, we'll have the chance to see whether GOP defense hawks are a strong enough force within the party to ride their election wave and restore American military strength," Zakheim wrote. "If not, another election victory will have failed to translate into effective policy – and Republicans will have only themselves to blame."
"During my four years as chairman, I've come to rely on Mac as a policy expert, a gifted communicator, a trusted confidant, and a friend," McKeon said. "He has skillfully helped our committee as vice chairman, and his national security smarts have earned the respect of both Congress and defense experts alike. But most importantly, Mac is a leader with a servant's heart. His devotion and loyalty is, above all, to the men and women of our military.
"The Armed Services Committee will be in the most capable of hands with Chairman-select Thornberry, and so will our Armed Forces. My heartfelt congratulations to him as he moves into this rewarding — and challenging — job." ■