It’s hard to think of a byelection anywhere, or even a bunch of them together, that have attracted so much interest. Burmese go to the polls on Sunday to fill just 40 vacancies in the 440-seat lower house of parliament, plus a handful of seats in the upper house and regional parliaments.

But in view of the fact that the general election a year and a half ago was widely seen as rigged and was boycotted by the main opposition party, the National League for Democracy, the prospect of a genuinely democratic exercise — even if for less than 10% of the parliament — is quite revolutionary, and a big step on Burma’s reform process.

Some background helps to understand its significance. The military seized power in Burma (now also called Myanmar) just on 50 years ago, and ruled without serious challenge until a popular uprising in 1988.

The uprising was suppressed, but the generals promised to hold elections in 1990, which it was assumed would be fraudulent. In fact they turned out to be reasonably free, and the NLD, under Aung San Suu Kyi, won in a landslide.

The military promptly took fright, annulled the results and continued to rule by force under a new leader, general Than Shwe. Then the cycle began again: further widespread protests in 2007, led by Buddhist monks, were suppressed but were followed by superficial concessions. A new constitution was approved in 2008, and the 2010 election led to the installation of a nominally civilian president, former general Thein Sein.

Since then, however, things have departed from the script. Burma has taken the reformist road with a vengeance: Aung San Suu Kyi has been released from house arrest and entered negotiations with the government, censorship has been relaxed, political prisoners have been released, free trade unions have been permitted, ceasefire agreements have been signed with rebel groups and international observers have been invited to observe Sunday’s polls.

It looks as if either Thein Sein, in total contrast to his background, has turned out to be a closet liberal, or else the military is playing an incredibly risky double game.

We know that authoritarian political systems can sometimes reform gradually from within. Mikhail Gorbachev’s dismantling of the apparatus of Soviet dictatorship is probably the most obvious example. But it’s a rare event and, as that case shows, the risks are considerable. More often, dictators open the window just slightly to try to appease critics or attract foreign aid, then either succeed in shutting it again or are overthrown in the attempt.

But although there is still some scepticism, change in Burma is looking more and more like the genuine article. With the momentum that has built up, re-imposing control would require a massive use of force, and the longer things continue the more difficult it would be. The country may have already reached the point where, even from the generals’ point of view, continued democratisation carries fewer risks than the alternatives.

Josh Frydenberg (not usually one of my favourite people) hit the right note last month in saying that “perhaps now, in President Thein Sein, the country has its own F.W. de Klerk, a political leader with the capacity to bring a reluctant establishment with him on the pathway to reform.”

Expectations are that the NLD will achieve something like a clean sweep of the seats on offer on Sunday, and its presence will add further impetus to a process already under way, namely the parliament behaving as a genuine forum for debate and a check on government power. A recent article in Inside Story quotes Burmese scholar Thant Myint-U: “Far from being a rubber stamp, parliament is today perhaps the most dynamic state institution, unburdened as a new institution by the inertia that threatens change in other parts of government”.

This is not unprecedented either. Some readers will remember the 1989 elections in Poland, where the Communist government conceded free elections for a third of the lower house of parliament. The opposition won the lot, and the former allies of the Communists, seeing the writing on the wall, suddenly started behaving like independent actors. The government lost control of parliament and was forced to agree to an opposition prime minister, and full democratisation soon followed.

Every country is different, and Burma’s road to freedom may well have more twists and turns to come. But if Sunday’s voting comes up to expectations it will do a lot to convince the remaining sceptics.