Presidents have had to sign or reject the entire bill.
For example, if the president wants a tax break for a state industry, Congress will add it to a military appropriations bill.
It is best for presidents to accept add-ons even if they don't like them in order to pass important legislation.
The line-item veto was supposed to be a new tool for presidents before it was ruled unconstitutional.
The 1996 line-item veto was favored by conservatives and was supposed to save money by allowing presidents to cut some items, like pork barrel projects, from spending bills without vetoing the entire package.
The law was declared unconstitutional by the Supreme Court because the Constitution says that all legislation should be passed by both houses and presented to the president for approval.
The vice president's role as presiding officer of the Senate is one of the president's key legislative powers.
When the Senate is evenly divided, vice presidents may cast a tie-breaking vote.
Recent examples show how important this is to presidential prerogatives.
Vice President Al Gore broke a tie in 1993 to allow President Clinton's first budget to pass.
The bill included tax increases and spending cuts that helped create a budget surplus.
Vice President Dick Cheney broke a tie vote on Bush's first budget, which undid some of the Clinton tax increases but also included numerous other tax reductions.
The pieces of legislation were hallmarks of the presidents' agendas.
In his first year in office, Pence broke six ties, more than any previous vice president in a single year, and continued at a good clip his second year.
When the Senate splits over controversial legislation, the president can count on the vice president to break a tie.
The president does not have the power to make law, but the power has grown over time and now is accepted.
It is possible for presidents to clarify how laws passed by Congress are to be implemented by specific agencies.
President Franklin Roosevelt's order to hold Japanese Americans in internment camps in World War II is one of the most significant presidential actions.
Signing statements are a quasi-legislative power that can increase the president's role as a policymaker, independent of Congress.
At the beginning of a president's term, executive orders tend to be released at a higher rate as the president immediately implements key policies and at the end of the term as the president tries to leave a legacy.
Donald Trump has been particularly aggressive in undoing his predecessor's executive actions since executive orders are not Congress-made laws.
Presidents can have a long-term impact on the judiciary, but in the short run their power over the courts is limited.
Their continued impact comes from nominating judges to the federal courts.
Supreme Court justices are the final arbiters of constitutional meaning, and the political philosophy of individual judges can affect how they interpret the law.
Since judges serve for life, presidential appointments have an effect.
Today's Supreme Court is more conservative than its predecessors due to the appointments made by Reagan and Bush.
Most of the judges appointed by Bush were conservatives.
Many Democrats felt that Clinton's appointees to the courts should have been more liberal.
Bush revived the conservative trend that was halted under Clinton, and his nomination of Elena Kagan caused some to worry that his selections would follow Clinton's more moderate record.
Obama's choices for the judiciary were fairly liberal.
Many of the appointments he made were blocked by Republicans in the Senate, however, and their refusal to recognize his final Supreme Court nominee with hearings was an unprecedented denial of power to shape the Court.
He nominated more women, Asians, and Hispanics than any previous president as well as twelve openly gay federal judges and the first Native American female judge in the country's history.
The Senate has approved people to the federal bench quickly now that there is no need for a filibuster.
Presidents can't always gauge the judicial philosophy of their appointees, but they can be disappointed in their choices.
Eisenhower appointed Chief Justice Earl Warren and Justice William Brennan, who turned out to be more liberal than the president had anticipated.
"Yes, two, and they are both sitting on the Supreme Court," Eisenhower said when asked if he had any regrets as president.
Roosevelt was one of the first to use the presidency as a platform to push his policy agenda.
He earned his reputation as the "trust buster" for his fight to ensure the rights of the common working man by pushing back against large corporate monopolies.
The Senate approval of federal judges is what limits the presidential power to appoint.
Most nominees have been approved.
Sometimes rejection is based on questions about the candidate's competence, but other times it is based on style and judicial philosophy.
One of the more controversial cases was the Senate's rejection of Robert Bork, President Reagan's Supreme Court nominee.
The nomination process has been affected by political polarization.
Many federal judgeships remained open because of the use of anonymous holds in the Senate, which allowed the party opposing the president to hold up nominations.
It is easier for a bare majority to have its way in shaping the courts now that both of those tools are gone.
The president's choice of judges for the federal district courts can be limited by the fact that the appointees reside in a state that has a veto power over the president's choice.
If a president ignores the custom of senatorial courtesy and pushes a nomination that is unpopular with one of the home state senators, fellow senators will refuse to confirm the nominee.
In the short term, presidents do little to affect court decisions.
They don't try to get judges to make decisions, and they don't try to get judges to make decisions for them.
When a president criticizes a federal judge, it's usually poorly received.