It is a close race. Just 48 hours before tomorrow's polls for 207 seats in the National Assembly, the lower house, newspaper forecasts give Ms Bhutto's Pakistan People's Party (PPP) a narrow edge over Mr Sharif's Pakistan Muslim League. Weary and hoarse, Ms Bhutto ended her campaign last night in the heart of enemy territory: Mr Sharif's Lahore constituency. Mr Sharif finished off with a rally of more than 10,000 supporters in a Rawalpindi park.
The contest has failed to ignite any enthusiasm among most Pakistanis. Both Ms Bhutto and Mr Sharif have served before as prime minister, and both were found lacking. Ms Bhutto's PPP was founded as a leftist, Islamic party championing the rights of Pakistan's poor and dispossessed. Yet many of its candidates, including Ms Bhutto, come from landed families wielding feudal power over their peasants.
Mr Sharif, a rich industrialist, offered himself as prime minister in 1990 as a pragmatist, a man who understood the desires of Pakistan's aspiring lower-middle classes. But his short-sighted, vote-grabbing scheme of importing 90,000 taxi-cabs, which the government sold at a loss, drained more than dollars 1bn ( pounds 670m) of Pakistan's foreign-exchange reserves and nearly plunged the country into bankruptcy.
By the PPP's own calculations, Ms Bhutto will find herself short of a parliamentary majority. She is hoping to scoop up backing from the smaller regional and religious parties.
The Punjab has been Mr Sharif's stronghold, but this time his traditional voters, the conservative urban middle-classes, are being swaying towards the Pakistan Islamic Front. Also, after Mr Sharif's quarrel with the president and the army, which led to his forced resignation as prime minister in July, he can no longer can lean on the state machinery as he did in the 1990 elections.