Liberal Senator James Paterson has got tongues wagging with his proposal to sell off the painting Blue Poles. Jackson Pollock’s Number 11, 1952, better known as Blue Poles, is the most famous artwork in the National Gallery of Australia’s collection.

“Some people feel like they’ve got a real attachment to Blue Poles, and I understand that,” Paterson argued this morning. “But I don’t think it’s a good enough reason for the Australian government to tie up such a significant amount of money in a single painting which is hung in a gallery in Canberra most of the year, and which most Australians won’t ever see face to face in their lifetimes.”

“Think about the Australian work that we could buy if we just quarantined half of that money to be reinvested in a current Australian artist, or Australian art for the gallery.”

It’s easy to dismiss Paterson’s gambit as a stunt or a troll, and of course many have done so this morning on social media. But I think Paterson’s proposal is worth considering carefully.

Most galleries own many more works than they can feasibly exhibit at any one time. The National Gallery is no exception. Indeed, it has less space than it used to. In recent times it has closed one of its spaces — ironically because of funding cuts imposed by the Coalition government.

Galleries do “deaccession” of works from time to time (removing an item from the gallery in order to sell it), particularly those they deem of lesser art, historical or curatorial interest. The proceeds are generally used to buy new or different works that can add to or enhance their current collection. In a time of real austerity for Australian culture (austerity imposed by Paterson’s government), we owe it to living artists working in Australia right now to consider whether the sale of an asset like this could help fund more local and contemporary expression.

There are a number of problems with this proposal, however. Do we really know that the proceeds of the sale would in fact be re-invested back in Australian culture? Would the National Gallery get to keep the cash, or would a grateful Mathias Cormann dump the money straight into consolidated revenue?

Even if the money were re-invested by the National Gallery, there are still many uncertainties. The gallery is currently struggling to keep the lights on, after years of efficiency dividends imposed by both Labor and the Coalition. The temptation would surely be to use some of the proceeds of such a sale to ease the crushing burden of the current austerity. Selling off a masterpiece to fund recurrent activity is the very worst possible outcome.

And then there is the issue of the National Gallery’s independence. Under former arts minister George Brandis, the Coalition has regularly meddled in the affairs of cultural institutions that are supposed to be independent and at arm’s length from the government — most notoriously, by taking $105 million off the Australia Council in 2015 to set up a ministerial slush fund. Given this recent history, Paterson’s intervention is another example of a worrying pattern of Coalition politicians fumbling in the affairs of statutorily independent cultural bodies.

There is a reason why governments appoint people like Gerard Vaughan to manage the nation’s iconic cultural institutions. The widely respected director knows a thing or two about art history and the visual arts market. Surely any decisions about the National Gallery’s collection are best left to Vaughan and the gallery’s board, rather than a first-term backbench senator with no obvious interest in culture.

And there is little doubt that Blue Poles is indeed a masterpiece. As one of Pollock’s largest canvasses, its sheer size alone makes it one of the most important works that Pollock ever painted. It’s also from the key period of Pollock’s career, his “drip paintings” period of the late 1940s and early 1950s.

Blue Poles is important for reasons above and beyond Pollock’s unorthodox genius. It’s impossible to tell the story of modern art without Pollock. The painter was championed by Clement Greenberg, the most influential art critic of the mid-20th century. Pollock has become synonymous with “abstract expressionism”, the name coined by Greenberg to describe the movement.

Abstract expressionism was the moment that the centre of the art world moved unequivocally to New York, and it set the scene for the rise of later art movements (opposed by Greenberg) like pop and minimalism. Pollock is the emblematic artist of abstract expressionism.

In other words, Blue Poles is an artwork of global historical significance. Transcending national borders, it belongs to the cultural memory of all humanity. The painting’s acquisition by the far-sighted James Mollison in the Whitlam years proved a turning point in Australian culture, from the inward-looking and apologetic Australia of the Menzies years, towards the increasingly confident and international cultural life that we enjoy today.

In this context, Paterson’s grim complaint that Blue Poles is “not … particularly tied to Australia’s cultural heritage, and it’s not [an artwork] that particularly speaks to our cultural experience” is not just jingoistic dog-whistling. It is also wrong.

Selling off a masterpiece is a highly symbolic act. It would signal to the world that Australia is no longer interested in the intrinsic value of culture. A masterpiece like Blue Poles is of incalculable value to the National Gallery. It anchors the gallery in public perception, and has become part of the mental map of art audiences in this country.

In no small part because of the controversy stirred up by its purchase, Blue Poles symbolises the long struggle in this nation against ignorance and philistinism. For that reason alone, it is part of the cultural landscape of all educated Australians.