The legal job market is tough and for many turning down a full-time job offer from a large law is something that is not considered. The question arises though of whether or not you should accept an offer even if you get a clear signal that the firm does not really want you. My answer is no but the decision will be guided by how badly you want the job. So how does this happen?
In the legal field, there are many organizations that track and publish statistics regarding how many summer associates are brought into the firm after their 2L year and how many are offered full-time jobs after they graduate. As many large firms want to maintain their statistic of offering 100% of their summer students jobs in order to attract the best students, they will at times give students a “cold offer.” A cold offer is something like this.
“John, your performance during the summer has not really been that great and we do not see that you have much of a future with the firm. That being said, we are going to make you an offer. You should really consider whether this place is the place for you and we strongly encourage you to do some soul searching before you accept the offer. Perhaps a large firm is not for you.”
This is of course a "strong" cold offer and there are variations of them. My personal opinion is that a cold offer is not a good thing and I would recommend turning it down unless you are desperate. If you do accept the offer, the firm is under no obligation to keep you after you start and you will be a “marked” person who will be the first to be let go if there is ever downsizing. Moreover, as your performance is already in question, you could be terminated with cause shortly after you start. Also, in the United States employment is “at will” which means an employer can terminate you even without cause. The ultimate decision is of course yours but these factors are something to consider. Also remember that if the firm does not want you, someone else will. Let your pride guide you and go somewhere where you are wanted.