Senate of Colombia

Electoral system[edit]

According to the Colombian Constitution, 100 senators (senadores) are elected from a single national constituency. The remaining two are elected in a special national constituency for Indigenous communities.


Colombian citizens living outside the country are eligible to vote, although, unlike in the lower house, they have no special representatives in the Senate.


For elections to the Senate in the national constituency, political parties or other movements and groups run single lists, with a number of candidates not exceeding the total number of seats to be filled. The current electoral system, adopted in 2003 and modified in 2009 and 2015, requires party lists to pass a 3% threshold in order to obtain representation. For the 2006 and 2010 elections, the threshold was set at 2%, before being raised by the 2009 reform to 3%.^[1]


Parties may run a closed list, with the order of candidates pre-determined, or opt for preferential voting (open list), where the position of candidates on the list is reordered based on the individual preference votes of the voters. In senatorial elections, voters choosing a party running a closed list only vote for the party list; voters who choose a party running an open list may indicate their candidate of preference among the names displayed on the ballot, if the voter does not indicate a preference and only votes for the party, the vote is valid for purposes of the threshold but not for reordering the list based on preferential votes.


For the two seats reserved to Indigenous communities, the electoral quota system is used (total votes divided by the total seats), with the threshold in this case being 30% of the electoral quota.