6.2.3, 6.2.4 - Comparing Congress and Parliament

Membership and representation

The way a chamber is selected affects whose interests it represents and the legitimacy it claims.

The US House's voting membership is apportioned by population among states, with members elected in districts for two-year terms. The Senate gives each state two senators, directly elected for six-year terms, with staggered elections. Both chambers therefore have electoral legitimacy, but represent different units. The Senate protects equal state representation while giving voters in less populous states greater representation per person; the House is more population-based but district boundaries and the distribution of votes affect representation.

The Commons has 650 constituency MPs, elected through first-past-the-post. The Lords is unelected, largely comprising appointed life peers, alongside bishops of the Church of England; it includes party members and independent crossbenchers. Hereditary status no longer gives a right to membership following the 2026 reform. This can supply expertise and members less dependent on immediate re-election, but creates a democratic-legitimacy objection absent from a directly elected US Senate. Appointment also permits political patronage. US Constitution and amendments, Commons and Lords roles, 2026 membership reform.

The useful comparison is that both countries combine a lower and upper chamber, but the US upper chamber has its own electoral mandate whereas the UK upper chamber generally claims revising expertise rather than equal democratic authority. Expertise is a possible strength, not proof that every peer is independent or every revision is better.

If you sit in 2027: “Bicameral” is newly explicit in Issue 4's US glossary; Congress already had two chambers in Issue 3. Use the accurate meaning in either series, and distinguish current Lords membership from the historical 92-hereditary-peer exception.

Equality in law-making

Equality between chambers depends on the power to approve or prevent legislation, rather than their size.

In the USA an ordinary bill normally requires the House and Senate to approve the same text before presidential consideration. One chamber cannot generally bypass the other. Both can amend and reject bills. Although revenue bills originate in the House, the Senate can amend them: origination is an exclusive starting power, not final House supremacy. A presidential veto can be overridden only with the necessary two-thirds votes in each chamber. The chambers are therefore broadly equal in ordinary law-making, despite their different specialised powers.

The Commons and Lords ordinarily both scrutinise and agree a bill, with amendments moving between them in “ping pong”. However, the Commons has financial privilege and the Parliament Acts can bypass the Lords for specified legislation when their conditions are met. A certified Money Bill can proceed after a one-month delay; many other eligible public bills can proceed after rejection in two sessions with the required interval. The Acts are subject to exceptions, including a bill extending Parliament's maximum duration. This is a constrained procedure, not a power to ignore the Lords whenever ministers choose. Parliament Acts explanation.

The UK Lords can therefore delay, revise and persuade, often winning concessions without exercising a permanent veto. The Commons possesses the stronger final position. US bicameral equality creates a further veto point, increasing the need for agreement and the possibility of gridlock. UK asymmetry helps an elected majority deliver policy, but may reduce the upper chamber's ability to stop an objectionable measure. These consequences are interpretations of the rules, and actual outcomes also depend on party alignments and political pressure.

The 2017 US healthcare repeal defeat demonstrates that Senate agreement matters even when an executive wants legislative change. Contrast the UK's statutory possibility of bypassing the Lords: no general equivalent lets a House majority enact a bill after repeated Senate opposition. Senate healthcare vote record.

Distinct powers and their limits

US chambers have important powers beyond ordinary legislation that do not have direct Commons–Lords equivalents.

The US House alone can impeach, bringing formal charges against a president or other impeachable official. The Senate tries the impeachment, with conviction requiring two-thirds of senators present. The House's strength is initiating accountability; its limit is that accusation does not itself remove anyone. The Senate's strength is the decisive trial; its high threshold can make conviction difficult.