It’s that time of the decade again.

With the final results of the 2020 Census in hand, legislators are rejiggering the boundaries of congressional districts, in order to ensure that each of their state’s US House members represent a nearly identical number of residents. All too often, though, the straightforward arithmetic of redistricting gets entangled in the complicated calculus of politics.

That’s the case this year in Massachusetts, where the Legislature’s joint redistricting committee recently unveiled a plan that makes a significant change in the congressional map: It would put all of Fall River into the Fourth Congressional District, currently represented by freshman Jake Auchincloss, while keeping nearby New Bedford in the Ninth District represented by six-term representative Bill Keating. Until now, Fall River has been divided between the two districts.

Is this an appalling plan? A terrific one? Depends whom you ask.

New Bedford Mayor Jon Mitchell, community activist Dax Crocker, and former Representative Joseph P. Kennedy III are in the appalled camp. They insist that putting New Bedford and Fall River in separate districts is a grave mistake, one that will dilute their influence in Washington and weaken two South Coast cities that share common challenges and demographics.

Conversely, a slew of Fall River notables, including Mayor Paul Coogan, City Council President Cliff Ponte, Jr., and state representatives Pat Haddad and Carol Fiola, issued a statement extolling the new map. “Fall River will be the biggest city in the Massachusetts Fourth and will no longer stand in any community’s shadow or be second to another community’s needs,” they wrote.

For his part, Auchincloss couldn’t be happier. “I want all of Fall River,” he told an interviewer in August. The Legislature’s proposed map not only grants that wish, it also relieves Auchincloss of Wellesley and Hopkinton, two towns that didn’t vote for him in last year’s Democratic primary. Such considerations have led Auchincloss critics, like analyst Mary Anne Marsh, to sneer that all of this map-tweaking is nothing but a “Jake Auchincloss incumbent protection plan.” Then again, the map is also intended to be an Ayanna Pressley incumbent protection plan. As one redistricting committee co-chairman, Representative Michael Moran of Brighton, acknowledged at a hearing on Tuesday, a top priority for the mapmakers was to ensure the predominance of nonwhite residents in Pressley’s Seventh District, thereby strengthening its majority-minority status.

However cynical, such machinations are par for the course: When politicians devise political districts for other politicians to compete in, the process does tend to get rather … political. But two additional points are worth making.

One is that elected officials aren’t infallible at reading electoral tea leaves.

Barney Frank was elected to represent the Fourth Congressional District in 1980 and the redistricting that followed that year’s census forced him to run for reelection against a long-time incumbent, Republican Representative Margaret Heckler. Two-thirds of the newly configured Fourth District came from territory Heckler had always represented (including Fall River and its suburbs). The smart money said Heckler couldn’t lose, and Frank agreed. “If you asked legislators to draw a map in which Barney Frank would never be a congressman again,” he fumed, “this would be it.”

But Frank beat Heckler easily, winning 60 percent of the vote. He spent the next 30 years in Congress. Moral of the story: The impact of redistricting may seem a foregone conclusion, but voters have the power to turn even the most confident electoral prediction on its head.

The second point is that squabbles like the one over the Legislature’s redrawn congressional map grow so bitter because the House is so small. At 331 million, the population of the United States in 2020 was far larger than it was in 2010 (308 million), which in turn was a huge increase over the population in 2000 (281 million). Yet the surge in the number of Americans hasn’t been matched by any rise in the number of seats in the “people’s house” in Washington. The number of US representatives has been locked at 435 for a century.

That’s not what the Framers of the Constitution intended. “I take for granted,” James Madison wrote in Federalist No. 55, “that the number of representatives will be augmented from time to time.” For most of American history, everyone took it for granted. After each Census, the number of House seats was increased; more Americans, it stood to reason, needed more representatives.

But Congress refused to enlarge the House after the 1920 Census. Many members resented the swelling ranks of urban and foreign-born residents, and balked at creating new seats to accommodate their numbers. In 1929, Congress passed a law permanently capping the size of the House. Ever since, districts have been redrawn — but there remain just 435 of them, no matter how the population grows.

As a result, the average congressional district today is home to more than 760,000 constituents — a number far too huge for effective representation. Each House member, Madison also wrote, “ought to be acquainted with the interests and circumstances of his constituents.” But when the average congressional district contains more people than the entire city of Boston, that’s not possible.

Congress created this problem and Congress can solve it. A simple law is all it would take to boost the number of representatives. I have argued previously for supersizing the House to 1,500 seats, which would shrink the average district to about 200,000 constituents. The benefits of expanding the House would be many: more competitive (yet less expensive) races, more compact districts, greater demographic diversity in Congress, increased contact between representatives and constituents, less monolithic party control of state delegations, an end to the Electoral College controversy, and less partisan gerrymandering.

And one more benefit: With many more districts per state, far less would ride on each post-Census redrawing of the map. Far-flung and dissimilar communities wouldn’t have to be shoehorned into the same district. Fall River and New Bedford, just for example, could anchor a coherent South Coast district of their own, and no longer be forced to compete with Cohasset or Brookline for their representative’s attention.

No doubt Capitol Hill’s entrenched incumbents would balk at the prospect of diluting their own power. It would take getting used to. But a larger, more accountable, more representative House would make the world’s oldest democracy more democratic. It may sound paradoxical but it’s true: America needs more members of Congress, and the sooner we get them, the better.

(Jeff Jacoby is a columnist for The Boston Globe).