Final answer:
Presidents use the veto power to block legislation and negotiate policies, but success varies based on Congress's makeup and public support. Vetoes can both shape legislation and cause political damage, with a historical override rate of only four percent.
Step-by-step explanation:
Presidents have leveraged the veto power as a significant tool in their legislative arsenal. Most vetoes occur when the president and Congress are controlled by opposing parties or when presidents face bills that go against their policy preferences. While historically, only about four percent of all vetoes have been overridden, the effectiveness and consequences of its use can greatly vary.
The veto serves not just to block unwanted legislation but also as a bargaining chip to shape policy. For example, during Bill Clinton's presidency, veto threats and the actual use of vetoes were instrumental in negotiating the welfare reform bill of 1996. However, vetoes can also alienate Congress members and sometimes lead to political damage, as seen with President Bush's threat to veto the 'patients' bill of rights', which created a perception that he was against patients' rights.
The rate of success for presidents in using the veto also depends on the level of their public support and the partisan makeup of Congress. This is more notable under divided government, where recent presidents are choosier about the legislation they endorse, supporting fewer bills but focusing on those of paramount importance to their agendas.
Although the line-item veto was declared unconstitutional, it represented an extension of the veto power. The president's success in using the veto power depends on various factors, including the makeup of Congress, public support, and the president's willingness to use it as a tool for negotiation rather than mere obstruction.