As Sen. Susan Collins vies for a sixth term in what will be a senatorial slugfest next year, a look at the 1972 defeat of Maine Sen. Margaret Chase Smith may offer useful lessons.

Much like Smith was, Collins is seen as an independent-minded Republican who appeals to moderates. Also like Smith, Collins has taken pride in never missing a chance to vote in the Senate.

So far, it’s worked out for her. In Smith’s case, though, it only went so far.

In the 1972 election that proved friendly to GOP contenders nationally, the much-admired Smith sought her fifth term at the age of 74 and came up short. The candidate who beat her, Democratic Rep. William Hathaway, told reporters after the votes were counted that he “wouldn’t have won” if Smith had been younger — even though his campaign paid no attention to her age.

The press, however, didn’t shy away from the subject. The Somerset Reporter, for instance, where Smith once worked, wrote an editorial headlined “Time for a change” that insisted, “Mrs. Smith can no longer possibly have the stamina necessary to keep pace with the grueling daily schedule demanded of an effective U.S. senator.”

“Perfect attendance and seniority are not enough to meet Maine’s representative needs today,” it read. “We need an energetic senator willing to fight for our state to provide more jobs and clean industry.”

And it wasn’t just age that sent Smith out to pasture. As well as steering clear of personal attacks on Smith, Hathaway leaned heavily on grass-roots organizing. Smith, meanwhile, hobbled her chances by campaigning only on weekends until shortly before Election Day.

While Smith avoided crowds, Hathaway visited most Maine towns twice and focused his spending on “low-budget, low-key television commercials, which showed him traversing Maine talking about small-town issues,” according to the New York Times.

Allison Kobzowicz, who wrote about the race for a 2019 thesis at Liberty University, found that Smith “had been so well-loved by Maine and so confident in the continued support of her voters that she overlooked and dismissed some key issues that caused her to lose credibility with her constituents in 1972.”

She said the senator “was unwilling to change her campaign style because of her rigid principles and its success in the past, and this caused her to look out of touch with many of Maine’s people.”

It didn’t help either, Kobzowicz said, that Smith’s “unstable relationship with the press caused reporters to engage in some unfair attacks about her age and frailty, and her response to these attacks only increased their damage.”

Smith also came up with the notion that “a coalition of outsiders,” including consumer activist Ralph Nader, had unfairly gone after her because they didn’t like her pro-war stance on Vietnam and support for President Richard Nixon. There was some truth to that. Hathaway called a Nader report detailing the pros and cons of everyone in Congress a considerable help to his campaign. But, he said, more helpful again was the “army of volunteers” he put together with help from the Democratic Party.

Looking ahead, Collins, who will be 73 next year, isn’t going to check out of the campaign. She knows better.

But there is something to be said for her opponent to avoid the sort of Washington-led, hard-hitting politicking that failed to help Sara Gideon in 2020.

Although Collins may be vulnerable today — the polls certainly indicate that she is — many Mainers still respect her. With these many parallels in mind, the low-key, issue-oriented challenge that put William Hathaway in the Senate half a century ago should be given close consideration by Democrats who wish to see Collins defeated next year.