Absolutely!  You may want to duplicate a campaign in order to split-test certain campaign settings.

You could test whether auto-optimization is more effective than manually optimizing the campaign yourself.

Different domain names could also be tested to see whether one performs better than the another.

To duplicate a campaign just click on the home icon and head back to the Dashboard. From here you can find the campaign you want to duplicate, and click on 'Duplicate' under ‘Options’.