We study the informational effectiveness of electoral campaigns. Voters may not think about all political issues and have incomplete information with regard to political positions of candidates. Nevertheless, we show that if candidates are allowed to microtarget voters with messages then election outcomes are as if voters have full awareness of political issues and complete information about candidates' political positions. Political competition is paramount for overcoming voters' limited awareness of political issues but unnecessary for overcoming just uncertainty about candidates' political positions. Our optimistic results break down if microtargeting is not allowed or voters lack political reasoning abilities. In such cases, negative campaigning comes to rescue, at least in the majoritarian model.