We focus on changes in technology and campaign management to study the documented simultaneous increase in campaign spending and polarization. In our model, some voters are ideological while others are impressionable. If the distribution of voters between types is endogenous and depends on parties' platform choices, our results show that a) an increase in the effectiveness of electoral advertising or a decrease in the electorate's political awareness, surely increases polarization and may also increase campaign spending, while b) a decrease in the cost of advertising does not affect neither polarization nor spending.