Slaves were too valuable to be used in building the C&O Canal in MD. They used Irish because they were expendable.
Those who died were scratched off and others "hired". There were no immigration requirements to meet at the time; Europe was off loading its excess as well as its trash.
At least they weren't on the dole created by politicians digging into the pocketbooks of others.
You must be really big on raising the Minimum Wage too. Can't have all those slaves working for less than $10/hr. You want the minimum wage raised?
Pray for W and Our Troops