With Washington trying to put together a US$700 billion rescue for the nation's financial system, the federal money sought by other projects is starting to look like small change.

You could buy yourself a war with that kind of money - the US has spent US$648 billion on Iraq war operations so far.

You could match Franklin Roosevelt on his New Deal to help Americans during the Great Depression of the 1930s and raise him billions more.

Even in a town where billions come and go without anyone blinking, the money that could go into the Wall Street rescue is eye-popping. The House on Monday voted down a proposed US$700 billion bailout package, but congressional leaders said they were committed to trying again.

What else could the government do with a US$700 billion blank cheque? There are, well, billions of possibilities.

It could ensure universal health care coverage for six years, for example, or upgrade the country's most deficient bridges four times over. All the work to upgrade coastal levees that's been done since Hurricane Katrina? It's a mere drop in the proverbial US$700 billion bucket - US$7 billion, or just 1 per cent.

You could run an entire country. US$700 billion is more than twice the size of the economy of Denmark, which had a GDP of US$312 billion in 2007.

US$700 billion would buy 70 Hubble-type space telescopes. Or about seven international space stations. It would finance the National Institutes of Health, the premier US medical research institute, for two decades. Or pay the US national intelligence budget for 15 years.

According to the Wall Street Journal, half the money Roosevelt spent on his New Deal programme to lift the country out of the Depression and banking crisis was for public works projects. For US$250 billion in today's dollars, the nation got: -8,000 parks -40,000 public buildings -72,000 schools But that's thinking small.

Presented with the presumptuous question of what could be done if the government suddenly came into a spare US$700 billion, scientist M. Sanjayan said he would 're-envision how we live on the planet sustainably.'

'Instead of bailing out corporations with US$700 billion, we could be bailing out nature,' said Mr Sanjayan, lead scientist for the private Nature Conservancy.

'We could fix all the harm we've done in the past but also get it right going into the future,' in the ways that people get energy, use water and procure food.

He's talking about everything from creating green jobs to boosting solar energy and protecting watersheds.

'I think you could do it for that kind of money,' he said.

Or, on a more mundane level, US$700 billion could pay the wages of 22 million average Americans for a year.

You could even shoot for the moon. The Apollo programme that put man on the moon in 1969 cost roughly US$164 billion in today's dollars.

Truth be told, the government doesn't really have this kind of money lying around to spend hither and thither.

But there are plenty of other possibilities for the pondering: