Wayne Swan doesn’t often come out with a killer line but he produced one yesterday after Malcolm Turnbull claimed credit for the banks passing on 0.8% of the rate cut.

“I know Mr Turnbull thinks that the whole world revolves around his ego,” Swan said before jetting off to the IMF meeting in the United States. “But there are some events in the world which are much bigger than Mr Turnbull’s ego.”

Well, that’s not literally true about the Zaphod Beeblebrox of Australian politics, but it’s a good line.

Turnbull’s ego isn’t his biggest problem at the moment. Having a big ego is a prerequisite in politics, and Turnbull has done more to justify having a hypertrophied sense of self than just about anyone else in Parliament. It’s that he can’t, or doesn’t want to, shift the focus off himself.

Turnbull’s claim that he had a role in the banks passing on 80% of the RBA cut came during a rather fraught interview with Fran Kelly yesterday morning. Much of the interview was about the semantics of what Turnbull had specifically said about banks, with Turnbull maintaining he hadn’t criticised the banks but only the Prime Minister and the Treasurer. And then, halfway through, Turnbull said:

I don’t think there’s anyone listening that imagines that the accountability I’ve called on the banks to give to their borrowers has not resulted in them passing on somewhat more than they ideally would have liked to pass on.

In other words, I have stood up for borrowers, and I think borrowers have got a better deal as a result.

An amazed Kelly asked him how much of the rate cut he took credit for. “I’m not taking credit for any particular amount of it,” Turnbull replied quickly, explaining that his call for accountability had made the banks do their sums more carefully about what they could pass on.

This meant the bulk of the interview ended being about Turnbull. Meantime, a financial firestorm is sweeping the world.

It’s not a hard-and-fast rule, but generally the more an Opposition Leader talks about him or herself, the worse a position they’re in. For a start, it means they’re not doing their main job: getting stuck into the Government. It also makes them look self-obsessed, and self-obsession has been the Liberal Party’s problem all year — and in fact for most of its last term in office as well.

It was only late in the interview with Kelly that Turnbull got on to what should be more fruitful ground for him. He pointed out, clearly and eloquently, that while banks were refusing to pass on the full rate cut, they were engaged in one of the biggest periods of consolidation in Australian financial history. Clearly they had sufficient profits to fuel their purchases of their competitors, despite crying poor on the cost of credit.

It was a theme he ran with when talking to Alan Jones on Tuesday morning, before the rate cut, where the questioning was altogether friendlier. Turnbull emphasised that different banks had different levels of dependence on international credit, raising the question of why they so persistently raise and lower rates in lockstep.

Of course it’s all well and good to make these observations, but another thing to suggest doing something about our banking oligopoly, which is using the financial crisis to undertake a process of “consolidation” that would otherwise take several years and extended bouts with the ACCC. It would be fantastic to see a poacher-turned-gamekeeper act from Turnbull on doing something about the financial sector that made his wealth for him.

Julie Bishop has been off the radar this week. The interest rate cut, the global equities meltdown, the Treasurer’s trip to the US, have all happened with nary a word from her. She has been on deck, but in Perth, where the current time difference means she struggles to get into the east coast media cycle. Terry McCrann cruelly remarked earlier this week that Bishop should be allowed to make a mess of her job so that we could get a “real” shadow Treasurer as soon as possible.

It was a stupid comment because the Opposition, having let Bishop take the job, is stuck with her – it can’t afford to engage in further musical cheers with any credibility, so it needs her to perform effectively.

As the financial crisis mounts, the Opposition risks being sidelined. When the going is good, there’s plenty of ammunition in demanding pension increases and complaining that banks haven’t passed on interest rate cuts. Kevin Rudd doesn’t feel comfortable with that sort of retail politics. But the going is now decidedly bad. We’re not quibbling over whether banks should pass on 0.1% of a 0.25% cut, we’re talking about whole percentage points. We’re not talking about how to spend the surplus, we’re wondering how much there’ll be left of it.

Rudd can now look properly Prime Ministerial, the Chief Wonk who can call the Chinese to check how their economy is going and talk about accepting political pain for the long-term good of the economy.

Turnbull needs to carve out his own space in the crisis. He’s far better equipped than Brendan Nelson was to do it, but he needs to stop talking about himself.