He went on to say "Where hostility to the United States in any interior locality shall be so great and universal as to prevent competent resident citizens from holding the Federal offices, there will be no attempt to force obnoxious strangers among the people for that object...The mails, unless repelled, will continue to be furnished in all parts of the Union. So far as possible the people everywhere shall have that sense of perfect security which is most favorable to calm thought and reflection."
So maybe all Lincoln wanted was to make sure that Davis got the birthday card he sent?
No, he probably thought that would be formal recognition of the Confederacy.