Answer:
An investment tax credit encourages business investment. This means that firms will buy more capital units, replacing its labor units. Th laid-off workers will be jobless and unemployment will increase. This must be the argument most likely to be used by union officials against the statute. An investment tax credit will increase Auto-manufacturer's capital-labor ratio thereby making labor relatively more expensive.
Auto-manufacturer's representative would argue that the statute is justified on the grounds of optimal input substitution. He may argue that while some workers do lose their jobs, the refusal to such proposal will induce auto-manufacturers to locate their business in foreign countries where cheap labor is available. In that case, there will be no job for the US workers. Hence, ti is better to have a partial loss of jobs than a complete one.