When the president of the United States (POTUS) uses a presidential veto, it doesn't necessarily mean that the bill won't become a law. The US Constitution gives Congress a means to sign a bill into law after a presidential veto has occurred. In order to overturn a presidential veto, both houses in Congress must vote to approve the bill by a two-thirds majority. In cases where a majority votes does not occur, bipartisanship — the act of finding common ground via compromise — can help override the veto by gaining a majority vote. Other alternatives include declaring a law as unconstitutional or ruling against same party affiliation.
Why Vetoes Occur
One of the deep concerns of the founders of the US was that any one branch of the government would seize power and take the country in any direction desired. This is why the presidential veto, and the ability to overturn it, exists. The presidential veto in the US is a means by which the POTUS can reject a proposed bill that has received a majority vote in both houses of the legislative branch of the government, the US House of Representatives and the US Senate.
When the president exercises his or her right to reject the bill and use the presidential veto, the bill is returned to the House or Senate, wherever the bill first started, with remarks from the president on why the bill is being rejected. Often, when the bill originates from a majority congress that is in opposition to the POTUS’ political party, vetoes are a means of defeating bills that the president feels are in opposition to his or her political aims as head of a political party.
Majority Vote and Bipartisanship
While the House of Representatives and the US Senate work together for the good of the country, they do not always agree with one another. In the case of a veto from the president, an agreement is necessary to overturn it. The House and Senate must have a majority vote of two-thirds from both parties to override the president's decision.
Realistically, it is difficult to overturn a presidential veto because there is seldom a two-thirds majority of a political party in both congressional houses. Though occasionally members of the minority party will vote with the majority party, this still may not amount to enough votes to represent a two-thirds majority. On the other hand, when the president appears to be acting against the interest of most members of Congress, regardless of party, bipartisanship to overturn a veto can occur to severely limit presidential powers.
Another alternative besides a majority vote may occur when Congress passes a law that is declared unconstitutional by the Supreme Court. This action by the Supreme Court may ultimately influence whether or not Congress will attempt to overturn a veto; if the Supreme Court appears to be in agreement with the president’s veto, the time it takes to try to create a law after veto has occurred may not be worth the effort for Congress. For example, when the majority of Justices of the Supreme Court belong to the same political party as the president, they may do all they can to uphold the veto, making it nearly impossible for Congress to win a majority vote.
On the other hand, when concern exists in both the Supreme Court and Congress that the president is abusing his or her authority through vetoing, the Supreme Court may rule against party affiliation, no matter how conservative or liberal their politics are. This may be done to uphold the right of Congress to pass laws that conform to the US Constitution and are perceived as being in the best interest of the country.