Question: Information:  - In the United States, Super Tuesday, in general, refers informally to one or more Tuesdays early in a United States presidential primary season when the greatest number of U.S. states hold primary elections and caucuses. More delegates to the presidential nominating conventions can be won on Super Tuesday than on any other single day of the primary calendar. Since Super Tuesday primaries and caucuses are typically held in a large number of states from geographically and socially diverse regions of the country, it typically represents a presidential candidate's first test of national electability. Thus, candidates seeking the presidency traditionally must do well on this day to help secure their party's nomination. In fact, convincing wins in Super Tuesday primaries have usually propelled candidates to their party's nomination. Super Tuesday is in either February or March of the presidential election year. During the 2016 election year, Super Tuesday was held on March 1.  - The Potomac primary (named after the river that splits the region), also called Chesapeake Tuesday, the Beltway primary, and the Crabcake primary, is the confluence of three Democratic presidential primaries and three Republican presidential primaries that takes place after Super Tuesday.  - The 2008 Virginia Republican primary took place on February 12 , 2008 . This was an open primary with 63 delegates ( 60 pledged delegates ) at stake in a winner take all format . The District of Columbia and Maryland both held primaries on the same day , referred to as the `` Potomac primary '' . John McCain won the primary , receiving all of Virginia 's delegates to the 2008 Republican National Convention .    Given the information, choose the subject and object entities that have the relation of 'instance of'.
Answer:
virginia republican primary , election