Correction: An earlier version of the article incorrectly identified the home state of the Senate Foreign Relations Committee chairman in 1978, when Cochran was first elected to the Senate. The chairman then was Sen. John J. Sparkman, and he was from Alabama, not Louisiana. This version has been corrected.

In a tight runoff contest, Sen. Thad Cochran manages to eke out a victory against his tea party challenger, Chris McDaniel.​ (WLOX)

When Thad Cochran won his first Senate race in 1978, he was succeeding the 73-year-old Judiciary Committee chairman from Mississippi. The 79-year-old senator who chaired the Foreign Relations Committee at the time hailed from Alabama. The 78-year-old Armed Services Committee chairman also came from Mississippi.

Back then, the Senate was ruled by men in their 70s from the Deep South.

On Tuesday, in a surprisingly strong showing, Cochran defeated his tea party challenger, state Sen. Chris McDaniel, proving that at least in some corners of the South, voters are willing to overlook his slowed-gait and his elderly tone, if it means their senator can still deliver.

The past decade of U.S. politics has dramatically altered the dynamics of congressional and presidential elections, often casting aside Washington experience for fresh-faced insurgents. That shift has been most dramatic among the once-mighty bloc of Southern conservatives, who for decades dominated the Senate.

Those shifts made Cochran the underdog heading into Tuesday’s Mississippi primary runoff, but the genteel 76-year-old incumbent spent three weeks pushing voters to stick with the century-old tradition in the South of keeping their senators long enough to accrue enough power so they could bring home the spoils from Washington.

In a surreal speech late Tuesday night, Mississippi Senate candidate Chris McDaniel railed against his own state's party and vowed that his fight isn't over. He did not concede. (Jeff Simon/The Washington Post)

In Mississippi, Cochran toured military bases and construction yards that he had poured federal dollars into during his six terms. Poised to reclaim the chairman’s gavel of the Appropriations Committee, he promised more federal funds for years to come — and an assortment of his state’s GOP elder statesmen poured millions of dollars into a furious TV campaign to remind voters of Cochran’s patronage, including a decided push to turn out traditional Democratic constituencies to vote in the Republican race.

McDaniel stuck to the national, anti-Washington script, pledging to rein in federal spending even if it meant less dollars for Mississippi. His loss Tuesday served as a crushing blow to Washington-based conservative activists who have suffered a series of defeats in other primaries, and had turned the runoff into a last stand to try to upend the establishment.

Instead, Cochran appears to have convinced enough voters that he was still up for the job, even though other Republicans say that is no longer the selling point it once was.

“You’re not going to get elected anymore, from where I live, by saying: Keep me there because I know how the game is played,” Sen. Lindsey O. Graham (R-S.C.), a 12-year veteran who won a contested primary two weeks ago, said Tuesday.

Collectively, a new generation of austerity-conscious Republicans has changed the argument for winning in the South. They want to tame government spending rather than continue the traditional flow of federal dollars into the region, championed by senators such as Cochran.

With Democrats in control of the Senate, Sen. Mary Landrieu (D-La.) is the only chairman from the region, and if Republicans win the majority in November, a handful of Republicans could claim gavels of committees with varying degrees of power. Cochran and Sen. Richard C. Shelby (R-Ala.), the 80-year-old ranking member of the Appropriations Committee who has been in the Senate for 28 years, are the only figures left on that side of the aisle who still embody the spirit of past chairmen such as the late John Stennis (D-Miss.) and Richard Russell (D-Ga.).

Shelby, first elected in 1986 and preparing to run for a sixth term in 2016, said he understands the rage that voters feel toward Washington institutions and how it has led to a new crop of leaders emerging from his region. “People are frustrated all over America. People are frustrated with the national debt. They’re frustrated that this place is a stalemate, at best,” he said.

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That’s not how Southerners viewed their senators’ roles in the first half of the 20th century. Back then they were mostly Democrats, such as Russell coming into office with FDR's “New Deal” agenda in 1933 and leaving during the Nixon administration in 1971.

Of the 25 senators who have served the longest in history, nine come from four states of the Deep South: Georgia, Mississippi, Louisiana and South Carolina.

Cochran, the 24-longest-serving senator, could vault into the top 10 if he serves out another full six-year term.

People such as Russell saw the federal government as the way to help steer federal resources into poor regions, sometimes through using clout to set up military bases in their states or through other federal agencies. In his more than 38 years in office, Russell chaired four panels, most importantly the Armed Services Committee, giving him great sway over Pentagon spending.

“They had a real stranglehold on committees,” where true power resided in the 1960s and 1970s, said Senate historian Donald Ritchie.

Those conservative Democrats were largely replaced by conservative Republicans, but the senators still held the view that a big part of their job was to bring home the bacon for their states. Stennis, who chaired Armed Services when Cochran arrived in 1979 and later ran Appropriations, was replaced in 1989 by Trent Lott, a Republican whose national image was the new confrontational southern conservatism.

Lott used that image to defeat Cochran in 1996 to become majority leader, but he never forgot his roots. Lott was ruthless when it came to protecting the shipyard of his hometown Pascagoula. Sometimes he threatened to steal business from competing yards in Maine, other times he simply added extra war ships into military spending bills that the Pentagon did not request.

Out of leadership, Cochran devoted his career to the traditionally bipartisan Appropriations Committee. In the last years when earmarks were allowed, Cochran regularly had the largest haul of funds directed to his state even though Republicans were in the minority.

Things began to shift under the feet of the new southern senators, such as Graham, 58, and Georgia’s Republican Sens. Saxby Chambliss, 70, and Johnny Isakson, 69. For years the trio fought for a massive infusion of federal dollars to deepen the ports in Savannah, Ga., and Charleston, S.C., to make them globally competitive.

They have struggled to keep their state’s congressional delegations unified on the key projects, as some anti-spending Republicans recently elected to the House questioned whether the federal government should play such a role.

Chambliss, faced with multiple primary challengers running on austerity platforms, bowed out of his 2014 election and announced he would retire after just two terms. In that campaign Rep. Jack Kingston (R-Ga.), a 22-year veteran with a prolific record of bringing home federal dollars, has run as a budget-cutter prepared to shrink spending, advancing into a July 22 runoff after a massive seven-candidate primary divided up the voters.

Graham said that the proliferation of the media and the swelling federal debt have made parochial concerns less important to voters in his state. “People have a more national view. We’re all about to go under together,” Graham said. “You’ve got to prove you have an effective voice.”

His predecessor, Strom Thurmond, held his seat for 471 / 2 years with a strong regional approach to governing — whether it came to helping his state’s defense industry or trying to defend the South’s Jim Crow laws.

Some Southern states have made an economic transition by welcoming manufacturing plants in with anti-union laws that give businesses better profit margins. Louisiana, Virginia, Texas and South Carolina all rank among the 20 lowest unemployment rates among the 50 states, with jobless rates at 5.3 percent or lower.

However, if there was one place where tradition and clout and federal dollars might matter, it was Mississippi. The unemployment rate there is 7.7 percent, third highest in the nation, so Cochran mounted an old-fashioned campaign built around his ability to deliver for the state — just as Stennis, Lott and others had done.

McDaniel likened the federal spending in his state to an addiction that thwarted the private sector. He dismissed his lack of seniority as something that every new senator must endure.

“Well,” he told an interviewer, “they’re all brand-new at one point or another, are they not?”

But at a final rally, Cochran stuck to the old-time script: his pledge was that he knew how to bring home dollars even in these tight budget times. “I think that experience is a very strong asset in determining how you allocate very scarce resources,” Cochran said.