Economists and others talk of ‘inflection points’ — supposed times when a major change happens (“tipping points” are similar ideas) — now the struggling US economy is reaching one of those.

Maybe not economically, but in terms of the confidence being generated by the surge in markets and the increasingly optimistic tone in official comments.

Federal Reserve chairman Ben Bernanke repeated his “green shoots” line (this time “tentative signs”) overnight that the economy was steadying and turning, and President Obama picked up on the idea in a speech saying there were signs of recovery, but that the US was not “out of the woods yet”.

Does he mean we’d better hurry and get out of the woods because the bears might get us, again?

If so, I’d watch the developing General Motors situation where a high risk game of chicken is being played between the company, the Administration, unions, bond holders and other creditors as this story from Reuters shows.

The risk of a General Motors Corp bankruptcy is rising, causing bondholders to pursue independent strategies to protect their interests if GM’s survival battle moves to bankruptcy court, two sources close to the government talks with GM said on Tuesday.

The Obama administration’s auto task force led by Steven Rattner is in its second week of talks in Detroit in an effort to revamp GM’s restructuring plan and wrest concessions from bondholders and labor, and is preparing a reduced term sheet for GM bondholders for about $28 billion of unsecured debt.

Until now, a 10-member bondholder committee has shown a united front, but cracks may be starting to show, leading to independent bankruptcy strategies, according to two sources familiar with the group.

With about 45 days for GM to present new restructuring plans before the government’s June 1 deadline, creditors are beginning to shift tactics to prepare for a possible Chapter 11 filing.

If the US markets can cope with a bankruptcy filing by GM then it will be the most positive sign to date (the cost is another thing). It could very well be the tipping point as investors realise the world hasn’t come to an end, again.

But while markets are more confident and seeing green shoots everywhere, the reality of the recessed economy is another thing. Everybody is waiting for the fertiliser to kick in, and hoping there’s not a late winter chill.

Corporate earnings reports from banks have lifted spirits, but then dampened them as more results from the likes of Johnson &Johnson and then Intel (after hours) and the slump in retail sales sent markets lower.

Johnson & Johnson did better than many analysts had said it would, but when they looked again at the numbers there were worries about the sustainability of drug and product revenues.

Likewise with Intel which saw earnings drop sharply, but the company was unable to get a clear outlook statement, even though it claimed the slump in computer sales had bottomed out.

Looking at US retail sales last month it’s no wonder there’s confusion, even as those “shoots” blind some to the reality.

For example Mr Bernanke talked about the “tentative signs” of improvement even as March retail sales fell by more than forecast.

Retail sales fell 1.1% in the month, including cars. The market got it very wrong in expecting a 0.3% rise. Excluding cars, sales fell 0.9%, compared with the forecast of a flat growth.

Spending on discretionary items such as furniture, clothing, restaurants and, particularly, electronics slumped, with only food and health experiencing a rise over the month. That’s a sign of consumers spending on the necessities of life, hunkered down and surviving. Remember at least 32 million Americans are dependant on Government food aid and they don’t make aggressive, free spending consumers.

It made for grim reading, and although the upward revisions to spending in February (a rise of 0.3%, instead a fall of 0.1%) and January (a rise of 1.9% instead of 1.2%) offset some of the impact (but made the slide even more apparent.

But economists point out that after falling at an annual rate of 25.5% in the 4th quarter of 2008, retail sales fell by around 4.9%, annual, in the March quarter of this year. That’s better news, but still bad for retailers, their employees and suppliers.

Another set of figures will worry Mr Bernanke and his fellow Feders: producer prices fell 1.2% in March, to be down 3.5% on a headline basis in the 12 months to March. On a core basis they were steady, and up 3.8% over the year: the difference is the drop in commodity prices, including oil. They will be watching the consumer inflation figures out tonight and wondering…”deflation..?”

But GM is the big test (with a warm act at Chrysler before then). 45 days to go — who will be first to blink?