1. [with object] obtain or bring about by discussion: he negotiated a new contract with the sellers
[no object] try to reach an agreement or compromise by discussion: they refused to negotiate with the rebels
2. find a way over or through (an obstacle or difficult route): she cautiously negotiated the hairpin bend
The leaders of the two US political parties demonstrated the modern way to negotiate over the stalemate to approve their budget in Congress. Each claimed to want to negotiate and each claimed the other would not do so. Each declared they would not negotiate on one policy each held dear; either support for or antagonism to the so-called Obamacare.
It was the form of negotiation where each insisted that because the other would not give them what they wanted that other was refusing to negotiate.
They were unable to negotiate [the passing of legislation] by discussion because they could not agree on one matter.
They were unable to negotiate to reach an agreement or compromise by discussion.
But then, should they?
If the matter on which they cannot agree is so important, maybe even a matter of truth, then it is reasonable to refuse to negotiate, to compromise.
Often it is possible to agree to disagree, to be tolerant of each other. In this case the country depended on a resolution to the disagreement, for a compromise solution or for one party to concede to the other.