of the executive branch may draft legislation and then ask senators or representatives to introduce these drafts into Congress. Additionally, the president may attempt to have Congress alter proposed legislation by threatening to veto that legislation unless requested changes are made. Promulgating regulations Many laws enacted by Congress do not address every possible detail, and either explicitly or implicitly delegate powers of implementation to an appropriate federal agency. As the head of the executive branch, presidents control a vast array of agencies that can issue regulations with little oversight from Congress. In the 20th century, critics charged that too many legislative and budgetary powers that should have belonged to Congress had slid into the hands of presidents. One critic charged that presidents could appoint a "virtual army of 'czars'—each wholly unaccountable to Congress yet tasked with spearheading major policy efforts for the White House". Presidents have been criticized for making signing statements when signing congressional legislation about how they understand a bill or plan to execute it. This practice has been criticized by the American Bar Association as unconstitutional. Conservative commentator George Will wrote of an "increasingly swollen executive branch" and "the eclipse of Congress". Convening and adjourning Congress To allow the government to act quickly in case of a major domestic or international crisis arising when Congress is not in session, the president is empowered by Article II, Section3 of the Constitution to call a special session of one or both houses of Congress. Since John Adams first did so in 1797, the president has called the full Congress to convene for a special session on 27 occasions. Harry S. Truman was the most recent to do so in July 1948 (the so-called "Turnip Day Session"). In addition, prior to ratification of the Twentieth Amendment in 1933, which brought forward the date on which Congress convenes from December to January, newly inaugurated presidents would routinely call the Senate to meet to confirm nominations or ratify treaties. In practice, the power has fallen into disuse in the modern era as Congress now formally remains in session year-round, convening pro forma sessions every three days even when ostensibly in recess. Correspondingly, the president is authorized to adjourn Congress if the House and Senate cannot agree on the time of adjournment; no president has ever had to exercise this power. Executive powers The president is head of the executive branch of the