Final answer:
Over recent decades, the personal staff workforces of House & Senate members have grown due to increased demands for constituency service, the need to navigate federal programs, and the professionalization of lobbying.
Step-by-step explanation:
In the last few decades, personal staff workforces hired by House & Senate members have increased significantly. This expansion is a consequence of various factors, including the legislation enacted post-World War II which amplified the volume of demands from citizens for assistance with federal programs and navigating bureaucratic systems. In response to these growing demands, members of Congress have continually added to their capacity to deliver assistance by expanding their personal staff. This has not only increased the size of their workforces but also altered the role of Congress members from focusing primarily on policymaking to engaging significantly in constituency service activities.
The growth in demand for these services has provided lawmakers with an opportunity to build credibility and a service-based relationship with their constituents. Morris P. Fiorina highlights the importance of constituency service, stating that it allows for an increased emphasis on nonpartisan district services, altering the meaning of the electoral choice and potentially swaying voters' preferences. Professionalization in lobbying has also coincided with the increase in sophistication of lobbying techniques, which has indirectly contributed to the professionalization of legislative staff as they navigate complex relationships and legislative demands.