Final answer:
The declining union membership rate in the United States can be attributed to several factors, including the shift from manufacturing to service industries, globalization and increased competition, and improved workplace protection laws.
Step-by-step explanation:
The driving forces for why there is a declining union membership rate in the United States can be attributed to several factors. One reason is the shift from manufacturing to service industries, which has led to a decrease in unionized jobs. Another factor is globalization and increased competition from foreign producers, which has put pressure on businesses to cut costs, including labor costs. Lastly, workplace protection laws have improved over time, reducing the need for unions to protect workers' rights.