The defendant placed his finger on the trigger, he fired the gun at the victim.
At the risk of sounding too big for my britches, as my grandmother would have said, I personally find it difficult to believe educated people commit these errors, but I see them every day.
There are essentially three ways to correct comma splices—join the independent clauses with a coordinating conjunction, make one clause dependent, or separate the clauses into two sentences.* Don’t let the term “coordinating conjunction” scare you. It is a fancy name for words we all use in most every sentence we write—and, but, yet, so, or, and nor.
Joining the ClausesIf you choose to join the clauses, you should use one of the 6 coordinating conjunctions listed above preceded by, not followed by, a comma.**
The defendant placed his finger on the trigger, and he fired the gun at the victim.
Making One Clause DependentIf you choose to make one clause dependent, you simply join the clauses with a comma.
When the defendant placed his finger on the trigger, he fired the gun at the victim.Because the defendant placed his finger on the trigger, he fired the fun at the victim.
Separating the ClausesIf you choose to separate the clauses, they should be separated into two sentences using a period, an exclamation point,*** or a question mark.
The defendant placed his finger on the trigger. He fired the gun at the victim.
*Technically, you also can separate them with a semicolon. I personally don’t recommend this option unless you have an appropriate understanding of the use of semicolons. It has been my experience that a large number of lawyers (and, perhaps, writers in general) do not.
**As with all grammar rules, this rule is not applicable 100% of the time. For example, in the following sentence, no comma is needed:
The defendant placed his finger on the trigger and fired the gun at the victim.
Without getting too technical, no comma is required in the sentence above because I’ve re-worded it so that it no longer has two independent clauses and the word “and” merely connects the compound verbs “placed” and “fired.” The clause “fired the gun” isn’t independent—it can’t stand on its own.
***I personally believe exclamation points should not be used in formal legal writing.