Nearly 100 years on - another century of wars - we have gone from Wilson to WikiLeaks.

The disclosure this week of a massive tranche of secret US diplomatic cables appears set to have a bigger impact on the business of diplomacy than Wilson's well-intended rhetoric about a world made fit and safe to live in.

But the exposure of diplomacy to public view has drawn quick condemnation from officials and commentators alike for damaging the cause of peace.

''It puts people's lives in danger, threatens our national security and undermines our efforts to work with other countries to solve shared problems,'' declared the US Secretary of State, Hillary Clinton.

Despite the warnings, the cables so far released have led to red faces rather than conflict, with candid assessments of foreign leaders (the ''increasingly erratic'' French President, Nicolas Sarkozy) and disparaging comments about countries (typical of Brazil, ''trying to be everyone's friend''). The perfidy of government has also been exposed, such as the British promise to America to ''put measures in place to protect your interests'' before a supposedly independent inquiry into the causes of the Iraq war.

But while embarrassment goes on - and will for months as WikiLeaks gradually releases more than 250,000 cables - diplomats everywhere must now confront wider questions.

What does this mean for the future of diplomacy? Will governments speak frankly to foreign representatives or fear private conversations could become public? And will diplomats be reluctant to put their thoughts and observations in writing for the same reason?

''This is bound to cause a lot of angst and embarrassment in the short term,'' says Gareth Evans, foreign minister in the Hawke and Keating governments.

''High-level diplomacy these days - as indeed it always has been - is a very personal business. I wince, for example, to think of Hillary Clinton now talking with Kazakhstan's leaders.''

Clinton was in the Central Asian nation this week for a summit on regional security. One of the leaked cables dating from 2008 said the leaders of the resource-rich country ''are able to indulge in their hobbies on a grand scale, whether flying Elton John to Kazakhstan for a concert or trading domestic property for a palace in the United Arab Emirates''.

But Evans believes the embarrassment will be short-lived, if only because every nation engages in such commentary.

''Even at the high level of personal embarrassment of this kind, even with Barack Obama calling [Britain's Prime Minister] David Cameron 'lightweight' and all that other stuff, you can overstate it because everyone talks the same way,'' Evans says.

Nor is it the first time such unflattering portraits of foreign leaders have come to light. Kevin Rudd was left spluttering on a visit to New Zealand in 2008 after an official Australian biography describing then prime minister Helen Clark as a left-wing ''control freak'' was mistakenly included in notes for the media.

Yet Evans is sure the practice of collating biographies will continue. ''There is always a need to pass on the more impressionistic stuff, the personality assessments and so on - whether they are simply reinforcing what's already out there in the media … or particularly if they change the popular perception in some way.''

The reason, Evans explains, is to better understand the person behind the public facade. Having a stronger understanding of foreign nations is precisely the reason to post diplomats overseas - or, as the old saying goes, sending an honest man to lie abroad for his country.

''It's not only a matter of being of salacious interest, that sort of gossip. You need to know that about the people with whom you're dealing - to take it at its face value and build it into your judgements when you're dealing with other people,'' he says.

''Let's be adult about this, we know there is that backwards-and-forwards stuff, and while things can be excruciatingly embarrassing, it's not necessarily all that much news to the people concerned.''

The biggest change Evans believes will result from the leaks will be even tighter controls on access to official information.

''Obviously there will be after this even greater care about how precisely you report things,'' he says. ''There will be stuff in highly classified cables or emails, with a much more limited distribution. There will be a reinforcement, yet again, of the tendency to rely on secure telephone conversations rather than putting it on paper. That's an unhappy development in terms of the wider availability of often very interesting information but I think there has been a steady move in that direction.''

In one sense, WikiLeaks has been almost as influential a non-government actor as al-Qaeda, considering its impact on the way officials do business. Imposing tighter controls on access to information would run counter to the lessons drawn after September 11, 2001. Security agencies were heavily criticised for secretive practices and not sharing information that might have warned of the attacks.

In the aftermath, the mantra in government circles changed from the strict application of the rule allowing access to information only to those with a ''need to know'' into a new culture of ''responsibility to share''.

Or as Obama put it on coming to office in January last year, speaking of the need for open government, ''Starting today, every agency and department should know that this administration stands on the side not of those who seek to withhold information but those who seek to make it known''.

But the willingness to share information across agencies raised the number of people with access to material and therefore the risk that it would leak. The WikiLeaks material appears not to have come from sources in the State Department but in the defence realm. Most suspicion has centred on Bradley Manning, the 23-year-old army private now in a Virginia military prison who is charged with ''transferring classified data'' and ''delivering national defence information to an unauthorised source''.

Close observers draw a distinction between the sharing of national security intelligence and the political reporting typical of diplomatic cables. But there is concern that a greater reliance on emails and secure phones rather than more widely distributed cables could keep information from reaching the right people.

''The problem is that this will cut the analytical community, both intelligence agencies and those who do analysis,'' says Ron Neumann, a former US ambassador to Afghanistan who is president of the American Academy for Diplomacy.

Neumann, who retired from diplomacy in 2007, says the restrictions will make it harder for analysts to contest the views of higher officials, who may have access to a wider range of material. ''This was very much the pattern under [former secretaries of state] Henry Kissinger and to some extent under James Baker,'' Neumann wrote in an an email exchange with this reporter.

''I do not expect the development to be a total shift. Rather, things will move back and forth, but on the whole the analytical community within government will be deprived of important information and the gap between analysts and policy makers is likely to widen, to the disservice of good policy making.''

Australia already applies severe restrictions to certain cables in the foreign service. So-called category A cables are widely distributed across Canberra and the diplomatic network. But category B cables are far more restricted.

''The fact is that category B cables are very, very closely guarded,'' says Michael Wesley, a former intelligence officer who is now executive director of the Lowy Institute. ''They are really reserved, with few exceptions, for people in the senior executive service.''

Wesley believes the WikiLeaks disclosure will reinforce a pattern where officials in the Department of Foreign Affairs and Trade are reluctant to write official correspondence because it could find its way into the public domain through leaks, increased parliamentary scrutiny or freedom of information legislation.

''DFAT has been plagued by leaks to the media - you bastards in the media - for years,'' Wesley says. ''You've seen, I think, over a decade a decline in diplomats' willingness to commit frank and fearless advice and commentary to formal cables.''

Wesley thinks the government is unlikely to go the other way by reassessing the need to highly classify material, thus reducing the pool of secret documents.

''To do that, you're performing self-censorship,'' he said. ''If you say to yourself as a government, 'Look, we are only going to report stuff that we are not going to be embarrassed about if it gets leaked,' then you change completely the character of diplomatic reporting.

''Diplomacy is made of the ability to make realistic and often harsh judgements about the people that you're dealing with. If you can't make those because you think it might turn up on Wikileaks some time, then you deprive your diplomacy of the nuance and the knowledge and the shared judgement that the cables allow.''

Neumann fears another consequence of the WikiLeaks disclosure - a loss of trust.

''The greater problem will be with things that don't happen because of the now well-founded belief that we're not good at keeping information private,'' he says.

''Pakistan, to take an example from one cable I noticed, refused to agree to a secret plan to remove some nuclear material … because they felt the plan would leak and expose them to criticism. They will now be confirmed in that judgment and it will be difficult or impossible to reopen the discussion.''

Neumann also believes the exposure of Russian and Chinese co-operation with the US to pressure Iran over its nuclear ambition could make Moscow and Beijing less likely to help in the future.

''Again, it will be difficult to assess the exact degree to which the leaks hinder future co-operation but, at least for a time, I think this a likely consequence,'' he says.

Officials are seeking to straddle twin messages, at once decrying the leaks while playing down the impact. Robert Gates, the US Secretary of State, is a good example. ''Is this embarrassing? Yes. Is it awkward? Yes. Consequences for US foreign policy? I think fairly modest,'' Gates said.

''The fact is, governments deal with the United States because it's in their interest, not because they like us, not because they trust us, and not because they believe we can keep secrets.''

As for the business of diplomacy, Evans doesn't regard the leaks as marking a fundamental change. Why? For one simple reason. ''People are always going to talk.''

Daniel Flitton is diplomatic editor of The Age.