It is nothing new to have foreign policy crises at election time in American history, whether Presidential elections or midterm Congressional elections!
Franklin D. Roosevelt in the Election of 1940, after Great Britain was being bombed by the Germans, and France had fallen to the Nazis.
Harry Truman in the Election of 1948, facing the Berlin Blockade Crisis with the Soviet Union.
Dwight D. Eisenhower in the Election of 1956, facing the Hungarian invasion by the Soviet Union and its Eastern European allies, and the Suez Crisis in the Middle East.
John F. Kennedy facing the Cuban Missile Crisis in the midterm election of 1962.
Lyndon B. Johnson facing opposition growing in the Vietnam War after the Tet Offensive, and the invasion of Czechoslovakia by the Soviet Union and its allies, in the Election of 1968.
Jimmy Carter facing the Afghanistan invasion by the Soviet Union, and the Iran Hostage Crisis, in the Election of 1980.
George H. W. Bush facing the Kuwaiti invasion by Iraq in the midterm election of 1990, leading to the Persian Gulf War.
George W. Bush facing the War on Terror, and the invasion of Afghanistan, and planned invasion of Iraq, in the midterm election of 2002.
And now, Barack Obama facing the Russian intervention in Ukraine, and the growing threat of ISIL (ISIS) in the Middle East, in the midterm election of 2014.