Here’s a Republican party political advertisement from 1988, claiming that Republican leaders will raise no taxes. 

The ad points out that Republicans have been cutting tax rates for the past 8 years, i.e. since 1980. In contrast, the ad states that, in 1984, Democratic leaders called for a major tax hike. 

The ad continues: In 1988, Democratic leaders are only promising that they’ll raise taxes as a “last resort.” In other words, they’re keeping open the possibility of raising taxes. 

The ad concludes that Democrats will raise taxes, Republicans won’t. So “Vote Republican” - it's that simple.