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John Ratcliffe, a Republican candidate for Texas' 4th Congressional district, says he doesn't feel guilty about trying to force the House's oldest serving member out of office.

He "stayed too long, promised too much, and became a part of the problem," Ratcliffe told ABC News. "Public service … should be about what the voters want."

Ratcliffe's target, 91-year-old GOP incumbent Rep. Ralph Hall, who has been a fixture on the Hill for 34 years. But for the first time since his congressional career began in 1980, Hall failed to garner the required 50 percent of the votes in the March 4 Republican primary and faces a runoff on May 27. In a staunchly conservative district, that vote will likely determine whether Hall will see an 18th term.

The Houston Chronicle calls the race the "fight of a very long lifetime." And the headline begs the question Ratcliffe is hoping you'll ask: Is Hall too far over the proverbial hill to continue serving on Capitol Hill?

In a recently-released ad, Ratcliffe, 48, wastes no time telling voters that Hall is no spring chicken.

"At 91, Ralph Hall has served admirably, but after four decades in Washington, the problems are getting worse … it's time for leaders who are focused on the next generation," he says in the ad.

True, Hall is significantly older than his colleagues: According to the Congressional Research Service, the average age of Members of the House was 57 at the start of this session. But though there's a congressional minimum age (25 for the House, 30 for the Senate), there's no legally-mandated maximum. And Hall is hardly the only member of congress to remain on the Hill into ripe old age.

The U.S. House's longest-serving Member, John Dingell, D-Mich., retired earlier this year at 87. Rep. John Conyers, D-Mich., also 87, is actively pursuing another term. And s ome, like Rep. Donald Millford Payne, D-N.J., who succumbed to colon cancer at 77 in 2012, stay until their death.

The Senate age records are even more impressive. Sen. Robert Byrd, D- W.Va., served until he passed away at 92 in 2010. Theodore Francis Green, D-R.I., retired from the Senate in 1961 at age 93. And Strom Thurmond, R- S.C., (whose questionable legacy included vehement opposition to the Civil Rights Act) was still in office at 100.

One Texas reporter sardonically suggested Ratcliffe's campaign adopt the slogan, "John Ratcliffe: He won't be dead soon!"

Ratcliffe, a former U.S. attorney, insists he's not concerned about Hall's age.

"It's an issue of time [in office], not age," Ratcliffe said. "What can he do [in his next term] that he hasn't had a chance to do in the past 34 years?"

Hall's office did not respond to requests for comment, but the congressman has been trying to spin his advanced years as a plus. In an ad titled, "Wrinkles," Hall points to the lines on his face and insists they are political battle scars.

"See this one? Got it taking on the liberals when they attacked our second amendment rights. These, when we fought 'em on Obamacare," Hall says. "Texas values are still worth fighting for, and by gosh, I've still got room for a few wrinkles."

The congressman has stated that his 18th term would be his last. But Ratcliffe, who asserts that Hall has "hinted" at retirement for years, says he couldn't just sit back and wait for the dean of the Texas Congressional delegation to retire.

"The reason I got in the race was the $17 trillion debt," Ratcliffe said. "Another two years - I'm afraid it will be 20 trillion dollars … None of us can afford to wait."

The race isn't exactly a dead heat. In the initial vote, Ratcliffe came away with 29 percent of the vote to Hall's 45 percent, but most pundits agree that Ratcliffe is within striking distance.

Hall's birthday was just a few days before the primary. And no, Ratcliffe says, he didn't send a birthday card.