When an individual is contesting for a local political office, he or she makes lots of promises to people. when the individual wins the election and assumes office, he or she is often unable to carry out the political promises. in the context of leadership traits, the individual lacks

I believe the answer is: integrity

In the concept of leadership, integrity refers to the quality of leaders that make them develop a strong moral principles in handling their responsibilities.
Leaders with high integrity tend to never make false promise to their followers, always fulfilling their obligation, and care about the well being of the people that they lead.

Alloy of metals is the answer