Joe Biden and Paul Ryan’s vice presidential debate on Thursday differed sharply from the first presidential debate.

Biden and Ryan took part in a contentious discussion of foreign policy and domestic issues.

Ryan gestured while making a point during the debate.

Biden reacted as Ryan spoke during the debate.

The debate was characterized by lively exchanges between the political rivals.

The debate was seen as critical for both campaigns.

The debate began with a discussion on foreign policy.

The early discussion touched on the Sept. 11 attack in Libya and on efforts to keep Iran from developing nuclear weapons.

Vice President Joe Biden and US Representative Paul Ryan shook hands at the start of the debate.

Moderator Martha Raddatz of ABC News addressed the crowd before the start of the debate.

Supporters rallied in Danville, Ky., site of tonight's vice presidential debate.

The debate was seen as critical to each party’s presidential ticket.

Hats were for sale outside the debate site.

A man displayed an anti-Obama sign near the debate site.