Why is big business being picked on? Australia's big businesses have been hit by a string of policy losses; the latest is Kevin Rudd's 'resource super profit tax'.

The Government is running deficits; but despite the global financial crisis Australia's big companies - particularly banks and resource companies - are producing record profits. So they're an obvious source of cash for the government; and big business doesn't vote.

The Government is also playing to a populist backlash against large companies. Australians see big business as gouging consumers to increase profits. They hate excessive CEO pay, and also recognise big business interests often conflict with the national interest.

The Opposition is also attacking big business. Tony Abbott wants to levy a $2.7 billion tax on big business to fund paid maternity leave. He is also flagging a slowing of big-business driven record immigration. But as a Conservative shouldn't Abbott be defending big business from Labor? Not necessarily. The Liberal Party should be 'pro- markets', not 'pro-big-business'.

Big business exists for one purpose only - to maximise profits. That mostly leads to efficient and desirable outcomes. But it also means it doesn't care about anything else, like the national interest. Governments, both Labor and Liberal, therefore have a role to check big business when its interests clash with the national interest; such as when our resource companies want to sell themselves to Chinese-government-owned companies regardless of national security issues.

But sometimes the pursuit of profits by big business means it also doesn't care about free markets. A government should be promoting and protecting free markets because they're the most efficient way of allocating resources. Big business does not equal free markets. Because its sole aim is to maximise profits, big business has a tendency to restrict competition so it can control markets and charge higher prices.

In the past decade or so big business has managed to co-opt financial buzz words like 'economic liberalism' and 'free markets' to mean 'pro-business'. It's like the star player in a team has convinced everyone he is the team - that if you question the star player, you question the team and are disloyal. But a good coach has the interests of the whole team a heart. Sometimes that means pulling the star down a peg or two - particularly when his ego is out of control - in the interests of the team. A government needs to promote and protect markets as a whole; not just the interests of the biggest companies. Sometimes that means curbing the interests of big business.

A University of Chicago academic, Luigi Zingales, argues there are actually "serious tensions" between a 'pro-market' agenda and a 'pro-business 'one. He says the Republicans in the US have become pro-business, rather than pro-markets. The problem is a 'pro-business' stance means government is susceptible to lobbying by business for outcomes that benefit the business, but are at odds with the national interest or free markets. It's what happened with Wall Street firms, which helped trigger the GFC.

Zingales says the Republicans need to reassert their economic liberal credentials. That means rejecting subsidies, holding companies financially accountable for mistakes, and not letting firms (such as Wall Street banks) become so big they can't be allowed to fail.

Politically, this is smart. A pro-markets stance taps into the populist backlash against big business. But it also provides an alternative to the Rudd and Obama 'big government' response to the global financial crisis. It directs the anti-big-business backlash, not into more government, but something positive - more efficient and freer markets.

The Liberal Party should also be mindful of the difference between being pro-markets and pro-business when it formulates policy.

In this context Abbott's $2.7 billion maternity leave tax on big business doesn't make sense. Yes, it is an attack on big business. But the attack is not to protect the national interest, nor to promote freer or more efficient markets. It is a tax to fund a budget hole for a policy everyone should contribute to. It is something Obama or Rudd would do and big business has a legitimate gripe.

Abbott should also be supporting the principle of a 'resource super profit tax'. It is a more efficient tax superior to state royalties that is in the national interest (Australians get more for business use of their non-renewable resources). That doesn't mean Abbott can't oppose it on the definition and mechanics of the tax; ie on the grounds it's too high, or the hurdle rate is too low, etc. But to simply take the side of mining companies because it is a pro-business stance is misguided.

Some may say it's sacrilege for 'conservatives' or the 'right' to attack big business. It's anything but. Big business does not always equate to the national interest; and big business does not always equate to free markets.

Ben Power is a writer, journalist and investor.