Forfeiture of Public Office

Some state officers are subject to recall.

United States officers are subject to impeachment or expulsion.

The Forfeiture of Office clause extends the Constitution's impeachment

and expulsion clauses to officers-elect or unsworn appointees,

but only for political fraud, coercion or bribery

(see Penalizing Political Fraud, Penalizing Political Coercion

because they interfere with the public’s ability to ordain and establish government. 

If the offenses are proven in a court of law the offender won't take the oath of office,

never coming under Congress’ jurisdiction as an officer. Forfeiture of the as-yet unsworn office will be added to any penalty the court imposes.

This consists with all relevant clauses (see Department of Justice Enforcement). 

Since expulsion proceedings are done in Congress, expelling a seated member for political fraud by speech or debate on the floor consists with the Speech or Debate clause. 

But every term installs a new, numbered Congress. When running for reelection,

an incumbent is running for an office he or she has not been sworn into yet. 

Incumbents who are running for reelection can be prosecuted as candidates for fraudulent speech or debate on the floor if it impacts reelection. The member doesn't hold the office concerned yet. Forfeiture of the as-yet unsworn office will be added to any penalty just as for a challenger.

This details and consists with the Speech or Debate clause because it is external to it.

No Loss of House Representation

This amendment doesn’t empower Congress to reduce House representation. [Its preliminary version enforced Amendment XIV’s existing Section 2 (see Voting Safeguards in History) but the public was concerned about its potential for abuse. This final version removed that.]

But we need to remember that when the Constitution grants a power, sooner or later it will be used. The Constitution empowers the House (in Amendment XIV) to reduce representation for denial or abridgment of voting, though not for any other reason.  ​​