Final answer:
Federal elections in the U.S. involve voting for House Representatives every two years, Senators every six years with staggered terms, and the President every four years. In the UK, parliamentary elections must happen at least every five years, but can be called earlier with a supermajority vote.
Step-by-step explanation:
Under legislation passed by Parliament, federal elections must occur at different intervals depending on the positions being contested. For instance, every two years, all members of the House of Representatives are up for re-election, ensuring close personal contact with constituents and remaining aware of their needs. Senators, however, are elected for six-year terms with only one-third of the Senate being up for re-election every two years due to staggered terms. The presidential election is held every four years, where voters participate in selecting the Electoral College votes for their state. In the case of the United Kingdom, parliamentary elections must take place at least every five years, though earlier elections can be called with a two-thirds parliamentary majority.
In summary, while the intervals for different types of elections vary, for the purpose of general federal elections, the term lengths are two years for Representatives, six years for Senators (with staggered terms), and four years for the President. Special circumstances and local laws can modify these intervals.