Contract liability is joint and several: that is, all partners are liable (“joint”) and each is “several.” (We usually do not use several in modern English to mean “each”; it’s an archaic usage.) But—and here’s the intrusion of entity theory—generally RUPA requires the judgment creditor to exhaust the partnership’s assets before going after the separate assets of a partner. Thus under RUPA the partners are guarantors of the partnership’s liabilities. 1
Under UPA, contract liability is joint only, not also several. This means the partners must be sued in a joint action brought against them all. A partner who is not named cannot later be sued by a creditor in a separate proceeding, though the ones who were named could see a proportionate contribution from the ones who were not.