The remedy is another ten percenter in Mr. Cotler's riding to explain that the statement was false.
It is hard to say how what was done can be undone if the statement is false. That is why the courts sometimes award damages by way of compensation.
But this does not really make up for what was done, because a person's reputation was damaged and, in some cases, the damage remains even though compensation has been paid.
It is impossible to verify whether the situation has really been corrected after defamation has been committed and a false statement has been made. If someone has a national reputation, then an apology at the national level is necessary. If someone has a local reputation, then an apology at the local level is necessary.