cron is running, but no anacron jobs run. It's not a localized thing: none of them have been running for quite some time. (Clearly, I wasn't paying attention.)
I've checked all the usual cron-like things, but this message is found in /var/log/syslog:
Jan 9 12:22:41 skmaiwlm anacron[31411]: Can't chdir to /var/spool/anacron: No such file or directory
The syslog message turned out to be the answer to my question. All I had to do was create /var/spool/anacron and I tested everything using a solution I found here
sudo mkdir /var/spool/anacron
sudo anacron -f -n
I then was able to watch things progress normally in /var/log/syslog:
sudo less +F /var/log/syslog
Jan 9 12:23:18 skmaiwlm anacron[31500]: Anacron 2.3 started on 2018-01-09
Jan 9 12:23:18 skmaiwlm anacron[31500]: Will run job `cron.daily'
Jan 9 12:23:18 skmaiwlm anacron[31500]: Will run job `cron.weekly'
Jan 9 12:23:18 skmaiwlm anacron[31500]: Will run job `cron.monthly'
Jan 9 12:23:18 skmaiwlm anacron[31500]: Jobs will be executed sequentially
Jan 9 12:23:18 skmaiwlm anacron[31500]: Job `cron.daily' started
System happiness restored.