Campaigns can be re-sent to the same contacts if needed. They can also be sent to failed orders only to prevent needing to create another campaign.
To do this you will need to navigate to your Campaign Dashboard.
Select the 'Campaigns' tab
Find and select the campaign you wish to re-send
In the top right corner find 'Actions' and then choose either to 'Re-send failed orders' or 'Re-send campaign'.