Nearly a year ago, former president John Mahama set the otherwise dull pre-campaign season agog with his promise to transform Ghana's development fortunes with a 24-hour economy (24HE) in his possible second term.   Almost immediately, some critics dismissed the strategy as impractical, arguing that Ghana's economy was too small to absorb any increase in output from 24-hour business operations. Mr. Mahama quieted them with the  disclosure that he would chair a special inter-sectoral team to accelerate exports and open up foreign markets for Ghanaian businesses.  The critics then regrouped under the banner that Ghana already had a 24-hour economy, including some light-manufacturing firms, mining companies, pharmacies and hospitals, the police service, other government services, and chop bars (although the last is a rarity, even in big cities). Others argued that it is impossible to get all businesses to operate 24 hours.  This, however, was a distortion of the strategy, originally proposed in Mr. Mahama's 40-year National Development Plan. It's about more than the handful of companies that currently operate around the clock, by default, not strategy.