PENANG STATE — Malaysia’s ruling coalition has since 1957 steered the country between race riots, a brief and stormy marriage with Singapore and a communist insurgency, to the country’s position today as one of the great economic success stories of the developing world. But now its 56-year run in power since independence from Great Britain could be headed for the rocks. Malaysians will vote in a new parliament on May 5, and polls show a coalition led by former government insider Anwar Ibrahim has a shot at winning control of Southeast Asia’s third largest economy. “This election is the first one that is not a foregone conclusion,” says Clive Kessler of the University of New South Wales. Despite economic growth under the current government, perception of corruption and growing calls for more democracy and greater accountability have dogged it, giving the opposition a foothold from which to challenge the government.