Until very recently, Colombia had an electoral system for the legislature that combined proportional representation with an allocation of seats by quotas and largest remainders. Multiple factions could present lists under the same party label. The largest-remainders formula was applied to factions, rather than parties, leading to party fragmentation and low party discipline.

The impact of the largest-remainders rule can be illustrated with an example. Consider a district with 1,000 voters and 10 seats (so the number of votes needed to gain a seat by quota is 100). Party A gets 650 votes, Party B gets 240, Party C gets 70, and Party D gets 40. Running as party lists, A would get 7 seats (6 by quota, 1 by remainder), B would get 2 (by quota), C would get 1 (by remainder), and D would get none. If Party B were to split into three equal factions of 80 votes each, the party would get 3 seats (all by remainder), taking one away from A. If Party A splits into eight equal factions, however, it would capture 8 seats (all by remainder), leaving only 2 seats (also by remainder) for the fragmented factions of Party B. It is easy to see that large parties, to maximize the number of seats, have incentives to fragment into small electoral vehicles (known in Colombia as operaciones avispa), most of which aim to elect a single individual to Congress.

These incentives for fragmentation were exacerbated just before the 1991 Constitution, when changes to the structure of the ballot were introduced, as well as the financing of parties. The party leadership, which had no control over the party label, after 1991 also lost control of the funds, which were directly allocated to the factions, further diminishing the influence of party leaders. As a result, the number of lists running for the lower house jumped from around 350 to more than 900 between 1990 and 2002. In 2002, 96 percent of the winning lists elected only one candidate to congress, the great majority of them by remainders. In this context, legislators have incentives to cater to their regional constituencies, rather than to follow the line of the party leaders, on whom they do not depend for reelection.