The term floor-crossing can be used in two different ways. The definition used here is the process when one Member of Parliament (or Council) ultimately leaves his or her political party in order to join another party or become an independent candidate.
The term was first used to describe the process when Members of the British House of Commons crossed the floor to join the group of people (members of another political party) that was seated on the opposite site of the floor.
In some cases, the term floor-crossing is used to denote the singular event of voting with another party on one particular and special question. This is the case in a few countries, where the Members of Parliament vote through their seating position and are allowed to change their seat for every vote, particularly in decisions without required party discipline.
When Members of Parliament leave their political party, the question is what happens to the seat. There are three main ways that legislation can deal with this:
The seat belongs to the political party
- If this is the case, the person who leaves (or is expelled from) his/her political party will lose their seat, and the party can decide whom they want to give it to. This strengthens the party organisation and keeps the political balance that voters decided on in the last election. This system is most common in countries with List PR electoral systems.
- One can argue that internal party democracy and consensus-building are strengthened if the seat is kept by the political party. If there are disagreements in the party or parliamentary group, the individual Member of Parliament may be more inclined to try to solve the problem if the seat is held by the party and does not belong to the Member of Parliament. Political party members are also empowered by this system, given that they have a say in deciding who gets the seat. In practice, it is often the next person on the list of the last election who gets the seat.
- On the other hand, party discipline may go too far, and individual Members of Parliament may be threatened with expulsion from the party (and thereby the parliament) if they do not vote according to the party line.
The seat belongs to the individual Member of Parliament, and he or she can keep the seat regardless of if they stay in the same political party
- This strengthens the role of the individual and also his or her links to the constituency. In this case, party discipline may be weakened, and some argue that individual Members of Parliament are less likely to seek consensus with party members and in the parliamentary group if they have the option to leave the party but to keep their seat at the same time. Floor-crossing is also seen by some as a justified way to respond to a changing political context and something that should be part of a dynamic and vivid party democracy.
- Floor-crossing tends to favour the ruling party and thus the government. An already weak opposition may shrink considerably through floor-crossing, which can have a negative impact on the balance of power and foster a climate of political instability and insecurity. Intensive floor-crossing of Members of Parliament leads to a low accountability in politics and may affect the legitimacy of the government.
- Floor-crossing practices have historically fostered bribery and corruption when parties try to convince other Members of Parliament to switch parties. Floor-crossers are also often disliked by the general public and accused of political opportunism and corruption. They are often perceived as having their own agenda outside the political party, trying to pursue their personal career objectives.
- Extensive floor-crossing undermines the principle of Proportional Representation, where votes are proportionally translated into seats. When a Member of Parliament crosses the floor, the balance of representation that is determined by the voters is distorted (Faull 2005). It is sometimes argued that floor-crossing violates the will of the voters and their right to choose between the candidates of one particular party. Voters do in fact rather elect candidates on the basis of party affiliation than on the basis of pure candidate preferences in most of the cases. The representatives should therefore not be free to choose party membership by themselves without regard to the voters (Faull 2005). Others say that those who claim that floor-crossing is violating the will of the voters do not understand the concept of a mandate and representation (Rapoo 2002a). They say that representation in fact means that Members of Parliament have a clear mandate to make decisions in the name of their constituents without having to seek approval of the voters between the elections.
- A high level of floor-crossing may reinforce alienation towards politics, mirrored in a decreasing voter turnout (Faulls 2005) among the population in a country. Voters may feel unrepresented and ignored and have no trust in the accountability and honesty of politicians. A lack of trust of the citizens in politics and the political system is fostered, and the ongoing process of democratization may be threatened. The legitimacy of a newly established political system may be in danger if the citizens lack trust in it. This is less true in cases where floor-crossing is allowed but not widespread.
The seat belongs neither to the party nor to the individual Member of Parliament.
- A by-election must be held to fill the seat. This system is used in countries with majority/plurality electoral systems. A by-election offers the opportunity to fill the vacant seat with a fresh candidate, and it allows the voters to express their will again. Voters may vote differently and thereby express discontent with the ruling parties.
- By-elections are smaller and therefore less costly than normal elections, but in some countries they will nevertheless put a significant burden on the budget, and seats are sometimes left vacant for long periods because of a lack of capacity to arrange by-elections.
- In some circumstances, by-elections can have a wider political impact than merely replacing individual members, and are seen as a mid-term test of the performance of the government. In addition, if the number of vacancies to be filled during a parliamentary term is large, this can lead to a change in the composition of the legislature and an altered power base for the government, or even a change in government.
