A President may persuade members of their own party to vote for a particular bill by B, denying campaign funds to members who oppose the bill.
The President is often thought to be the leader of whatever party they are a member of, giving them a tremendous amount of power when it comes to the raising of money as they are the top draw.
So, a President can use campaign funding as a stick and a carrot to get members of Congress to vote a particular way.
If the member in Congress is in the opposition, they are out of luck.
They realized that they could not keep the United States from talking over the Florida<span> territory so in 1819 </span>Spain<span> agreed to </span>sell Florida<span> to the United States. The Adams-Onis Treaty was approved by </span>Spain<span> and the United States in 1821.</span>