How can one start a process and monitor its syslog messages?

I would like to start a process and monitor its LOG_DEBUG syslog messages.

I know that I can change the filter of an already running process with syslog -c process (and then monitor its messages with syslog -w -k Sender process), but that requires the process already to be running and furthermore fills up logfiles with messages that I only need temporarily.

Is my only option to change the running configuration with syslog -config, then later restore the configuration once I have read the messages I want? Surely there is a "better" way.