The rule of last antecedent is a trap

29 Nov 23

An oft-cited canon of statutory and contractual construction is the rule of last antecedent, which specifies that a qualifying or modifying clause operates to qualify or modify only the last, i.e. the immediately preceding, word or phrase.

This rule is implicated ubiquitously, with nearly every contract. It's a massive trap for many lawyers. 

Consider the following clause:

Subject to the termination provisions of this Agreement, this Agreement shall be effective from the date it is made and shall continue in force for a period of five years from the date it is made, and thereafter for successive five-year terms unless and until terminated by one year prior notice in writing by either party.

Does the "unless and until terminated" clause apply to the initial five year term and successive five year terms, or only to the latter?

What if the clause was worded like this instead:

Subject to the termination provisions of this Agreement, this Agreement shall be effective from the date it is made and shall continue in force for a period of five years from the date it is made, and thereafter for successive five-year terms, unless and until terminated by one year prior notice in writing by either party.

Does the new comma before the modifying clause ensure that the qualifier applies to both the initial and successive five year terms?

Ken Adams believes that this is expecting too much from our simple comma.


The lawyers of Redline confront this trap and devise strategies for avoiding it.