The literature on political actors’ media appearances has repeatedly documented the so-called incumbency bonus (that parties and politicians in government have more media coverage than those in the opposition). This bias is normally attributed to news criteria that reflect political power, such as relevance and the elite status of actors. Supplementing existing perspectives, this study puts forward a new explanation of the incumbency bonus. The article argues that variations in the media dominance of incumbents are the result of the interplay between journalistic norms and political context. Outside election campaigns, political news is driven by the ‘watch dog’ norm. Thus the media focus on societal problems, which produces a critical emphasis on incumbent actors. But when party competition intensifies, either during campaigns or when issues become salient, the norm of objective and impartial journalism results in a more balanced coverage where challengers increase their presence. The argument receives support through multivariate models of incumbent and challenger appearances in Danish radio news broadcasts over a twenty-year period. Finally, in terms of democratic implications, the importance of the watchdog norm challenges the assumption that the incumbency bonus constitutes an electoral asset. Since media dominance is closely related to government responsibility for all kinds of problems, incumbent support is found to dwindle with increased media appearances.