William Howard Taft (September 15, 1857 March 8, 1930) was the 27th president of the United States (19091913) and the tenth chief justice of the United States (19211930), the only person to have held both offices. Taft was elected president in 1908, the chosen successor of Theodore Roosevelt, but was defeated for reelection in 1912 by Woodrow Wilson after Roosevelt split the Republican vote by running as a third-party candidate. In 1921, President Warren G. Harding appointed Taft to be chief justice, a position he held until a month before his death.

Taft was born in Cincinnati, Ohio, in 1857. His father, Alphonso Taft, was a U.S. attorney general and secretary of war. Taft attended Yale and joined the Skull and Bones, of which his father was a founding member. After becoming a lawyer, Taft was appointed a judge while still in his twenties. He continued a rapid rise, being named solicitor general and a judge of the Sixth Circuit Court of Appeals. In 1901, President William McKinley appointed Taft civilian governor of the Philippines. In 1904, Roosevelt made him Secretary of War, and he became Roosevelt's hand-picked successor. Despite his personal ambition to become chief justice, Taft declined repeated offers of appointment to the Supreme Court of the United States, believing his political work to be more important.

With Roosevelt's help, Taft had little opposition for the Republican nomination for president in 1908 and easily defeated William Jennings Bryan for the presidency in that November's election. In the White House, he focused on East Asia more than European affairs and repeatedly intervened to prop up or remove Latin American governments. Taft sought reductions to trade tariffs, then a major source of governmental income, but the resulting bill was heavily influenced by special interests. His administration was filled with conflict between the Republican Party's conservative wing, with which Taft often sympathized, and its progressive wing, toward which Roosevelt moved more and more. Controversies over conservation and antitrust cases filed by the Taft administration served to further separate the two men. Roosevelt challenged Taft for renomination in 1912. Taft used his control of the party machinery to gain a bare majority of delegates and Roosevelt bolted the party. The split left Taft with little chance of reelection, and he took only Utah and Vermont in Wilson's victory.

After leaving office, Taft returned to Yale as a professor, continuing his political activity and working against war through the League to Enforce Peace. In 1921, Harding appointed Taft chief justice, an office he had long sought. Chief Justice Taft was a conservative on business issues, and under him there were advances in individual rights. In poor health, he resigned in February 1930, and died the following month. He was buried at Arlington National Cemetery, the first president and first Supreme Court justice to be interred there. Taft is generally listed near the middle in historians' rankings of U.S. presidents.

The president of the United States (POTUS) is the head of state and head of government of the United States of America. The president directs the executive branch of the federal government and is the commander-in-chief of the United States Armed Forces.

The power of the presidency has grown substantially since the office's establishment in 1789. While presidential power has ebbed and flowed over time, the presidency has played an increasingly strong role in American political life since the beginning of the 20th century, with a notable expansion during the presidency of Franklin D. Roosevelt. In contemporary times, the president is also looked upon as one of the world's most powerful political figures as the leader of the only remaining global superpower. As the leader of the nation with the largest economy by nominal GDP, the president possesses significant domestic and international hard and soft power.

Article II of the Constitution establishes the executive branch of the federal government and vests the executive power in the president. The power includes the execution and enforcement of federal law and the responsibility to appoint federal executive, diplomatic, regulatory, and judicial officers. Based on constitutional provisions empowering the president to appoint and receive ambassadors and conclude treaties with foreign powers, and on subsequent laws enacted by Congress, the modern presidency has primary responsibility for conducting U.S. foreign policy. The role includes responsibility for directing the world's most expensive military, which has the second largest nuclear arsenal.

The president also plays a leading role in federal legislation and domestic policymaking. As part of the system of checks and balances, Article I, Section 7 of the Constitution gives the president the power to sign or veto federal legislation. Since modern presidents are also typically viewed as the leaders of their political parties, major policymaking is significantly shaped by the outcome of presidential elections, with presidents taking an active role in promoting their policy priorities to members of Congress who are often electorally dependent on the president. In recent decades, presidents have also made increasing use of executive orders, agency regulations, and judicial appointments to shape domestic policy.

The president is elected indirectly through the Electoral College to a four-year term, along with the vice president. Under the Twenty-second Amendment, ratified in 1951, no person who has been elected to two presidential terms may be elected to a third. In addition, nine vice presidents have become president by virtue of a president's intra-term death or resignation. In all, 45 individuals have served 46 presidencies spanning 58 full four-year terms.Joe Biden is the 46th and current president of the United States, having assumed office on January 20, 2021.