It’s awfully tempting to sit back and watch the stoush over an iron ore inquiry between the government and Fortescue chairman Andrew Forrest on the one hand, and Rio Tinto and BHP on the other, popcorn in hand, and reflect on how times have changed.

It’s five years since the Coalition and the big iron ore producers combined to lead a blatantly dishonest campaign against a mining super profits tax, screaming “sovereign risk” and warning that the only beneficiaries would be rival iron ore producers. Forrest cheered them on, of course, despite not actually paying any tax, and led negotiations with Kevin Rudd until Rudd was knocked off, and Rio, BHP and the world’s biggest tax-dodger Glencore were allowed to rewrite the tax. The highlight of that campaign was Tony Abbott declaring, during the 2010 election campaign, that Zambia was a safer place for mining investment than Australia. Oddly, independent analysts assessed Australia as the world’s best place for mining investment for the last four years Labor was in power.

Now there’s trouble in paradise: the iron ore price has collapsed and BHP and Rio Tinto are exploiting their economies of scale and lower-cost production to force higher-cost producers out. Andrew Forrest, having tried to talk up an iron ore cartel before the Australian Competition and Consumer Commission fired a shot across his bow, has launched a public relations campaign — complete with a Twitter account that doesn’t tweet, and an AstroTurf website — to find a way to stop his competitors.

And the big miners’ erstwhile close friends in the Coalition appear divided on whether to help him. Tony Abbott supports a parliamentary inquiry, as does Mathias Cormann, who as a Western Australian could normally be relied on as a good egg by Rio and BHP, but who, as Finance Minister, has seen up close exactly what the iron ore price collapse has done to the Coalition’s budget ambitions. Industry Minister Ian Macfarlane and Trade Minister Andrew Robb, on the other hand, are less than keen.

BHP and Rio are screaming blue murder. Indeed, it’s surprising the magic phrase “sovereign risk” hasn’t been uttered by them yet — that responsibility fell to Bill Shorten who, presumably stifling a grin, warned today, somewhat malapropistically, of “a real cloud over our sovereign risk” from the inquiry.

The Prime Minister says an inquiry wouldn’t be a “witchhunt”, but that’s exactly what it would be. BHP and Rio Tinto are already under great pressure over revelations of their extensive tax-dodging. A parliamentary inquiry into their costs, pricing and production decisions would intensify that pressure.

But while it would be amusing to see BHP and Rio Tinto executives on the rack before a parliamentary committee, just what would be the point of the committee? To establish why the iron ore price has collapsed? The price was always going to fall as a result of a historic expansion in investment in production capacity, but it has coincided with the commodity’s biggest customer entering a comparative economic slowdown. To identify ways to force BHP and Rio Tinto to cut production? (Or to slap a tax on their profits to discourage them?) And even if the inquiry succeeded in discouraging exports, why wouldn’t our competitors, like Vale and Anglo-American, simply ramp up production themselves to seize the available market share? For all their lies, tax-dodging and ridiculous rhetoric, Rio and BHP are merely doing what we normally encourage businesses to do and compete as effectively as possible.

At least Labor’s mining tax, however poorly thought-through and executed, was sourced from the Henry tax review. This appears to simply be crass populism from a government that has proved a fair-weather friend indeed when it comes to the free market.