Michael Ritchie's 1972 film The Candidate is among the best movies ever made on political campaigning. Robert Redford plays the neophyte Democratic candidate, Bill McKay, who runs in an apparently hopeless race for the US Senate against the Nixonian incumbent, Crocker Jarmon (Don Porter).

Along the way, McKay is guided by a hard-headed campaign manager, Marvin Lucas (Peter Boyle), who causes McKay to shed all his idealism and embrace compromises that will get him across the line with the voters. In one memorable scene, McKay even wins the support of the notorious Teamsters Union.

Against the odds, McKay wins.

He becomes a US senator-elect for California, but at the end of the film he turns to his campaign manager and asks plaintively: "What do we do now?" He has won office but he doesn't know what to do with the power it conveys.

What is striking about McCarthy's win is that, unlike most previous speakers from both sides of the aisle, he seems not to have any kind of platform or agenda, let alone a program for the 118th congress.

If this is sounding a tad familiar, then we are looking at the recent 15-ballot battle for the speakership of the US House of Representatives. Eventually Kevin McCarthy of California was endorsed, after many and varied concessions were made to the fevered-right of his own Republican Party, grouped mainly in the Freedom Caucus.

What is striking about McCarthy's win is that, unlike most previous speakers from both sides of the aisle, he seems not to have any kind of platform or agenda, let alone a program for the 118th congress. Consider, by way of contrast, Republican Newt Ging-rich's 10-point Contract with America of 1994.

McCarthy should have done better, given his working-class background (his father was a Bakersfield firefighter) and his leadership service in the California State Assembly in Sacramento.

Unfortunately, McCarthy's ambition to be Speaker had achieved a certain notoriety that was almost to the point of ridicule.

It is clear this was his driving motivation, and therein lies real danger. British prime minister Stanley Baldwin warned against newspaper proprietors who sought "power without responsibility". Power without purpose is surely the politics of the empty, self-satisfying gesture.

Speakers of the US House of Representatives, who are second in the line of presidential succession, actually matter. They determine the legislative agenda for the house and the committees that facilitate it.

The most powerful Speaker, Joseph Gurney Cannon (Republican, Illinois), served from 1903 to 1911 and was a dominant figure.

He could be ruthless to the point of embarrassment, but he also had a facility for sharp exchanges, including within his own Republican ranks. He once described progressive leader Theodore Roosevelt as having "no more use for the constitution than a tomcat has for a marriage licence".

Sam Rayburn (Democrat, Texas) could be affable but equally ruthless, serving three times as Speaker of the house - from 1940 to 1947, from 1949 to 1953 and finally from 1955 to 1961 - displaying his resilience by returning to the Speaker's chair. He demonstrated instrumental leadership from the New Deal through to World War II.

The recent Speaker who retrieved the gavel for the Democratic Party is of course Nancy Pelosi (Democrat, California).

Pelosi, who has just left the Speaker's chair, will be regarded by historians generally, and particularly by American chroniclers, as one of the great speakers.

Pelosi was under constant attack from her Republican detractors, many of whom focused on the liberalism of her constituency in the Castro District of San Francisco. But this misread Pelosi in a fundamental way. She was actually the daughter of a Democratic family from Baltimore, Maryland, and she grew up with politics argued furiously at the dinner table.

The reason this ballot was so important, not only for Americans but for international politics, is to be found in the concessions McCarthy made to the extremes.

What Pelosi learned from her father, Thomas Ludwig John D'Alesandro, Democratic congressman for Maryland, and her mayoral brother Tom stayed with her. Above everything else, she was taught the necessity to win.

And as Speaker she registered some extraordinary wins, from the Affordable Care Act during the time of president Barack Obama, to the Biden administration's signature American Rescue Plan, the Build Back Better agenda and Bipartisan Infrastructure Law that has won support across the aisle.

And so we arrive at an interesting contrast to the speakership vote logjam that dominated the House of Representatives for five days and almost led to a melee on the house floor late last Friday night.

At the same time, President Joe Biden was in Kentucky with Senate Republican leader Mitch McConnell announcing funding to upgrade the notoriously dilapidated Brent Spence Bridge, which connects the states of Ohio and Kentucky.

Meanwhile, in the house, the Democratic minority voted as a bloc for Hakeem Jeffries of New York. Rather than appeasing some of the deranged on the Republican right, McCarthy could have reached across and outflanked the obstructive. But this was never contemplated.

Instead, McCarthy has brought Donald Trump back into focus because Trump played a role in the background by mobilising votes for McCarthy's leadership. Just when we thought it was safe to go wading in the tidal pool in Washington, Trump has reemerged as a Republican playmaker.

The reason this ballot was so important, not only for Americans but for international politics, is to be found in the concessions McCarthy made to the extremes.

In particular, the potential for congress to default on the American debt ceiling is considerably enhanced. Ideologues seldom hear reason and if the Freedom Caucus does not get its way then a potential disaster looms for the global economy.

A paralysing government shutdown emerged during the Clinton administration in 1995, when Gingrich led the charge as Speaker. It reached absurdity, where Clinton paid for the White House Christmas tree to be lit up on Pennsylvania Avenue out of his own pocket, before the Republican congress blinked.

Defence spending is going to be subject to increased scrutiny, although there are probably sufficient Republican hard heads to prevent any serious damage to the American strategic posture.

Nonetheless, greater instability is with us. One dissenting vote on the floor of the house can now put the speakership in play. This will be too tempting for some of the limelight seekers. Power without responsibility does that to some people.

It is a universal truth: the politics of seeking power without purpose is ultimately ruinous.

Ultimately the baubles and the titles mean little, if nothing at all.

The perceptive recorder of the infant American Republic, Alexis de Tocqueville, once observed pessimistically: "I do not know if the people of the United States would vote for superior men if they ran for office, but there can be no doubt that such men do not run." May the men and women of the 118th congress rise to the occasion. That's what they should do now.