Power of veto
The use of the veto has changed in recent years. In the earlier part of the twentieth century, the veto was used extensively — President Roosevelt famously vetoed 635 bills in total — and it was a principal means of asserting executive power when the executive was relatively weak. It is now used more sparingly, and tends to be seen as a sign of weakness. Its use suggests that the president has lost control of the agenda, if Congress is willing to pass legislation in defiance of his stated preferences, especially if Congress is controlled by the president's party. However, in the later stages of a presidency, or when faced by a Congress controlled by the opposition party, the veto may be the only way a president has of exerting influence.
That said, a lack of presidential vetoes may not necessarily be a sign of strength either. The first 5 1/2 years of the Bush presidency saw no vetoes at all until the veto of the Stem Cell Research Enhancement Act in July 2006, an unprecedentedly long period. Sympathisers saw this as the product of the president's domination. However critics saw it either as the product of indifference, when the president should have been keeping the budget under control, or as the president misguidedly wanting to project an image of strength and seeing the veto as inconsistent with the image of a powerful, agenda-setting leadership.
The Obama presidency has seen no significant vetoes, and presents a different picture again of the dynamics surrounding its use. In his first 2 years, the president and the Democratic-controlled Congress were, unsurprisingly, sufficiently in harmony to make use of the veto superfluous.
During his full two terms, Barack Obama used 12 regular vetoes. Congress failed to override the first 11 but succeeded on the twelfth. This was in September 2016 when President Obama vetoed the Justice Against Sponsors of Terrorism Act which would have allowed families of victims of the September 11 terrorist attacks to sue the government of Saudi Arabia for any role they played in the plot. In his veto message to Congress, Obama said that the legislation would ‘undermine core US interests’ and ‘create complications’ in diplomatic relations with other countries.
During his one term, President Trump used his regular veto power ten times, of which one (his ninth) was overridden by Congress.