Article II, Section 3, of the U.S. Constitution gives the president power to convene Congress, or either house, “on extraordinary occasions.” Usually, when the president calls for an extra session he indicates the exact matter that needs the attention of Congress. However, once convened, Congress cannot be limited in the subject matter that it will consider. The president is also empowered by the Constitution to adjourn Congress “at such time as he may think proper” when the House and Senate disagree with respect to the time for adjournment; however, to date no president has exercised this power. Many constitutional experts believe the provision applies only in the case of extraordinary sessions.