Republican Tim Burns and Democrat Mark Critz are both up with their first ads of the special election for Rep. John Murtha's (D-Pa.) seat.

Critz's ad focuses on his role in an effort to rescue nine trapped miners in 2002. He repeatedly mentions the late congressman, whom he worked for as district director.

Burns's ad focuses on his upbringing in Johnstown, Pa., and his conservative stances on abortion and guns.

Both men appear to be going to their base right away, with Critz hoping to attract voters who would have voted for Murtha. There will be a lot of them on special election day, May 18, because Democratic turnout is expected to be high for contested governor and Senate primaries. Critz appears to be wagering on that advantage.

Burns, meanwhile, seems to be appealing to the district's cultural conservatism.

These ads will be most voters' first glimpses at the two candidates.