As far as legislation goes, the presidents options are very limited. The last two years of Clinton's presidency he faced a republican controlled congress. This is a variable factor of every presidency, but if you are unfortunate to have this effect, then it becomes difficult to pass legislation. If there is not a major swing in congress, then your legislation will not be passed. In this point the power of persuasion is the only option a president has, if he cannot persuade his own party to vote on party lines, and the opposing party to not vote on their lines, then the legislation will fail.
The president also has the power to appoint judges at district, appeal and Supreme Court levels. This is argued as an important power, but it has its limits. After the nomination to the supreme court which is the most superior of all courts, has been made, then the senate begins it's confirmation process. If the senate does not reach a simple majority, as seen with Bork for example in 1987.
With this in mind, the president's power comes down to one thing: persuasion. This may be done in a variety of ways. The most sucessful way is to telephone individual congressman and try and pursuade them that way. President Raegan was extremely good at this. Another way is helping with legislation, i.e passing one piece of legislation and not vetoing it if congress passes his legislation. A simple trade.
However, in actual fact the president has much more than the power to persuade. He has many options in a lot of areas, though one of them is persuasion, and is the main power under the circumstances of late Clinton for example, the others play a major part if a president has control of the senate and or the house of representatives.
The most important power a president has is the power to appoint Supreme Court judges. This gives a president the chance to have their image in place for a long period of time, after they are president. Some presidents are lucky enough to appoint a lot of judges like Raegen and bush, who together appointed 5 of the 9 justices. Though the arguement against this being a true power is that it must be confirmed by the senate, but if Bush senior was to be faced with appointments then he would have no problem with a republican controlled congress in getting his choices passed. However, so far he hasn't been that lucky. Presidents who get a chance to appoint are lucky, and they put a lot of time into deciding who they should appoint. The FBI background checks and all the media coverage show it's importance.
Another important and influencial power is the fact that the president is the commander in chief. Congress has only the power to declare war, not bomb places. If the president gives the order to bomb somewhere, then it happens. Congress cannot check it, and if they do, they cannot stop it. However, the limit on this is that the president cannot declare war on another country without the approval of congress.
A presidents power to negotiate treaties is what makes him seen as a powerful figure abroad. Though this requires a 2/3 majority from the senate to confirm it, it is a very useful power. It is increasingly useful when a presidents party has a strong majority in the senate. However, if the president does not have a 2/3 majority in the senate, which is more than likely, he will have to use the power of persuasion.
In conclusion, the president has a number of powers, not just persuasion. However, in the circumstances that for example he is facing a congress held by the opposition party, then the power of persuasion becomes ever more important.
