One-hundred-and-twenty years ago, when the debate over Federation was at its height, the rivalry between Sydney and Melbourne over which should become Australia's capital was intense.

It was not, in fact, all that dissimilar to the rivalries that existed between America's founding colonies in the wake of the revolutionary war a century before.

That dispute was resolved by the decision, in 1790, to create a dedicated "capital district" on the borders of Maryland and Virginia, both of which donated territory to the cause.

Resolving that what had worked for our American cousins would do just as well Down Under, Federation's founders chose Canberra.

The intention, as with Washington, was to make the new city the home of the head of state, the legislature, the most senior court in the land and the head offices of an embryonic national public service.

It was a great vision, and one that worked well for the better part of a century. Unfortunately our elected leaders, particularly those from the conservative side of the chamber who often use this city's name as an expletive when on the campaign trail, have forgotten the Australian Capital Territory's reason for being.

Scott Morrison, who recently spoke at length about the "Canberra bubble", is the latest PM to make the Harbour City, and Kirribilli House, his principal place of residence following the example set by John Howard in 1997.

While Tony Abbott never moved into the Lodge he can be forgiven on the grounds the building was undergoing an extensive, and expensive, makeover for the whole of his time in office.

The Turnbulls, who moved in in 2016, actually bucked the trend by choosing to use their Point Piper mansion as their Sydney-side digs, giving Kirribilli the cold shoulder.

The only Labor PMs to have boycotted The Lodge were James Scullin, who felt it was too costly to staff and maintain during the Great Depression, and Ben Chifley who kept his friends close and his enemies closer by living in the Hotel Kurrajong, a well-known ALP haunt back in the day.

While, in the eyes of some, decisions by individual PMs to snub Canberra and the Lodge are of little consequence, they could not be more wrong. The city and the residence are potent symbols of national unity that represent a massive and sustained investment by generations of Australians.

It is the same short-sightedness that drives the narrative within the National Party about decentralising government departments and agencies to the bush.

That push runs counter to the view the national executive, and its subsidiary departments and agencies, would work best if key people were able to meet face to face.

Canberra is bigger than any individual politician or political party.

It would be timely and appropriate for the leaders of both the government and the opposition to formally acknowledge The Lodge as the official residence of the Prime Minister and that this city is the headquarters of the federal public service.