Congress' inability to consistently provide leadership on broad national issues is due to:

A. the lack of talented leadership in Congress.
B. constitutional restrictions on Congress' lawmaking powers.
C. the constant threat of a presidential veto.
D. the fragmented nature of Congress.

the biggest obstacle to effective congressional oversight is

a. its inadequacy as a mean to control bureaucracy

To figure out the answer to this question, let's break down each option and discuss how it might contribute to Congress' inability to consistently provide leadership on broad national issues:

A. the lack of talented leadership in Congress.
If the lack of talented leadership is the cause, it implies that the individuals elected as leaders in Congress may not possess the necessary skills, experience, or vision to effectively lead and address broad national issues. To determine whether this option is accurate, we would need to examine the qualifications and performance of the leaders in Congress.

B. constitutional restrictions on Congress' lawmaking powers.
The Constitution outlines the powers and limitations of Congress. If constitutional restrictions hinder Congress' ability to pass laws or take action on broad national issues, this could explain why they are unable to provide consistent leadership. To confirm this possibility, one would need to study the relevant constitutional provisions and determine any limitations they place on Congress' powers.

C. the constant threat of a presidential veto.
The President possesses the power to veto legislation passed by Congress, which can hinder the ability of Congress to pass laws on national issues. If Congress is consistently faced with the threat of a presidential veto, they may be cautious about proposing or passing potentially controversial legislation. To investigate this possibility, one would need to analyze instances where the President has vetoed Congress' legislation and assess its impact.

D. the fragmented nature of Congress.
Congress is composed of two chambers, the House of Representatives and the Senate, each representing different constituencies and having distinct roles and powers. If the fragmented nature of Congress, with its differing priorities and competing interests, leads to difficulties in consensus-building and providing cohesive leadership, this could explain the issue. To determine if fragmentation is the primary factor, one would need to examine the dynamics and decision-making processes within Congress.

In conclusion, to pinpoint the main reason for Congress' inability to consistently provide leadership on broad national issues, further analysis is necessary. This might involve evaluating the qualifications of congressional leaders, studying constitutional limitations on Congress' powers, considering the impact of presidential vetoes, and examining the effects of a fragmented structure within Congress.