Floor crossing explained: What it means for voters in Canada

The facts on how Canadians elect MPs, how Parliament functions, and what happens when a representative changes parties mid-term.

What Canadians actually vote for

In Canada’s federal elections, voters do not vote directly for a Prime Minister.

Instead, each person casts a ballot for a local candidate in their riding. The country is divided into 343 ridings, and each riding elects one Member of Parliament to represent that area in Ottawa. The candidate with the highest number of votes wins, even if they do not receive a majority. This is known as the first-past-the-post system.

• Canada has 343 seats in the House of Commons, each tied to a specific geographic riding
• A party needs at least 172 seats to form a majority government and govern without relying on other parties
• The Prime Minister is typically the leader of the party that wins the most seats, not someone elected directly by voters nationwide

This structure means voters are choosing a local representative first, and the national government is formed based on the total number of those local results.

What happens after an election

Once the votes are counted and MPs are elected, Parliament is formed.

Each MP travels to Ottawa and takes a seat in the House of Commons. Most MPs align themselves with a political party, forming what is known as a caucus. These party groupings determine how legislation is proposed, debated, and voted on.

• The party with the most elected MPs is invited to form government and lead the country
• Other parties form the opposition, holding the government to account through debate and questioning
• MPs typically vote along party lines, but they are not legally required to do so in every case

This system creates both cooperation and competition between parties, especially in minority governments where support from other parties is often needed to pass laws.

What is “floor crossing”?

Floor crossing refers to a situation where an elected MP changes their political affiliation during their term in office.

Rather than waiting for the next election, the MP makes a decision to leave their current party and either join another or sit independently. The phrase comes from the layout of the House of Commons, where government and opposition members sit across from each other.

• An MP may leave their party voluntarily due to disagreements, political strategy, or changing priorities
• They may join another party if they align more closely with its direction or leadership
• In some cases, MPs choose to sit as independents without formal party affiliation

This is a political decision made by the individual MP and does not require approval from voters or a formal vote in Parliament.

Is floor crossing allowed in Canada?

Yes. Floor crossing is fully permitted under Canada’s political and legal framework.

Canada does not have legislation that restricts MPs from changing parties once elected. The system is built on the principle that MPs are elected as individuals and are free to exercise their judgment throughout their term.

• There is no federal law that prevents an MP from leaving or joining a political party
• The Constitution and parliamentary conventions allow MPs to act independently of party control
• There is no legal mechanism that forces an MP to resign their seat after switching parties

Some countries have introduced anti-defection laws that require MPs to stay with their party or trigger a new election if they leave. Canada has not adopted this approach.

How common is it?

Floor crossing has occurred at various points throughout Canadian political history.

While it is not an everyday occurrence, it is also not rare. It tends to happen more often during minority governments or periods of political instability, when party dynamics are more fluid.

• Floor crossing has been part of Canadian politics since Confederation
• Several MPs have changed party affiliation during recent Parliaments
• On April 8, 2026, Sarnia-Lambton MP Marilyn Gladu crossed the floor, moving from the Conservative Party to the Liberal Party

Each instance is handled individually, but the process and rules remain the same.

What changes when an MP switches parties?

When an MP crosses the floor, the effects are immediate inside Parliament.

The MP physically changes where they sit in the House of Commons and becomes part of their new party’s caucus. Their vote now contributes to that party’s total during legislative decisions.

• The MP begins voting with their new party, influencing outcomes on bills and motions
• Party seat counts in the House of Commons are updated right away
• In close or minority governments, even a single MP switching sides can affect the balance of power

These changes can have broader implications for how easily a government can pass legislation or maintain confidence in the House.

Do voters get another say?

Not right away.

When an MP changes parties, there is no requirement for a by-election in that riding. The MP continues to serve until the next scheduled federal election unless they choose to resign.

• A by-election is only triggered if an MP steps down or their seat becomes vacant for another reason
• Voters do not automatically get to re-cast their vote after a party switch
• The next opportunity for voters to respond is during the next general election

At that point, constituents can decide whether to support the MP again or choose a different candidate.

What happens next

After a floor crossing, Parliament continues operating without interruption.

There is no formal approval process required, and no pause in legislative work. The change is recorded, and the MP continues their duties under their new political affiliation.

• The MP continues representing their riding in debates, votes, and committee work
• Party standings are updated to reflect the new distribution of seats
• Government operations and parliamentary proceedings continue as normal

The shift is political in nature, but it does not disrupt the legal functioning of Parliament.

Why the system works this way

Canada’s parliamentary system is designed to prioritize the role of the individual representative.

The idea is that MPs are elected to make decisions on behalf of their constituents, not to be permanently bound to a party label. This allows for flexibility, but also means that party affiliation can change during a term.

• MPs are expected to represent their riding’s interests while exercising independent judgment
• Political parties organize Parliament, but they do not legally control an MP’s seat
• The system reflects a balance between party structure and individual responsibility

This approach has been maintained over time, even as debates continue about whether rules around floor crossing should change.

Bottom line

• Canadians vote for a local MP, not directly for a Prime Minister
• The party with the most MPs forms government
• MPs are allowed to change political parties at any time
• No by-election is required when a party switch happens
• Voters respond at the next general election

This is a long-standing feature of Canada’s parliamentary system, and one that can shape how governments are formed and how decisions are made in Ottawa.

Editors Note: Updated 4:50pm April 15, 2026. The article has been updated to reflect the 2022 Redistribution of Federal Electoral Districts, which saw the boundaries of the previous 338 federal electoral districts increase to 343 districts.