So, if you cut taxes and venture into something as expensive as warfare debt will go up. But taxation is a much stronger ideological indicator than debt level, since it directly influences the distribution of wealth. Choosing to finance the Iraq war et al without raising taxes was an ideological decision.
There has always been plenty of right wingers willing to get their countries into debt to finance military costs, its not a useful indicator of a politicians position on the left-right scale.
Non-Defense spending also
increased significantly under Bush, and he enacted a ton of new spending initiatives, such as Medicare Part D, No Child Left Behind, and a
record number of subsidy programs. Clearly he was not a fiscal conservative.