The "Diplomatic Reserve Corps Act of 2026" amends the Foreign Service Act of 1980 to establish a Diplomatic Reserve Corps within the Department of State. This Corps is designed as an independent personnel system, separate from the Foreign Service, to maintain a reserve of trained personnel available for active service when required by the Secretary of State, the Department, or the Foreign Service. Its primary purpose is to assist in the discharge of their responsibilities and functions as authorized by law. The Corps is structured into four elements: the Senior Diplomatic Reserve, the Senior Diplomatic Retiree Reserve, the Diplomatic Reserve, and the Diplomatic Retiree Reserve. The Secretary of State is responsible for administering and directing the Corps, coordinating its activities with the Department's needs. Recruitment efforts are mandated to be broad and representative of the American people, with an authorized strength growing from 250 in fiscal year 2026 to 1,000 after fiscal year 2028. Eligibility for appointment requires U.S. citizenship, a minimum age of 21, and meeting prescribed physical, mental, and professional qualifications, with affirmative consideration for veterans. Members are prohibited from simultaneously serving in a uniformed service. The bill establishes salary classes and schedules for Corps members, generally conforming to Foreign Service pay scales, with basic pay computed hourly for active service. Compensation includes performance pay, within-class salary increases, and special differentials for additional work. Members are eligible for health care benefits through the Federal Employees Health Benefits Program (FEHBP) and the Foreign Service Health Program. The bill also provides for service awards, death gratuities, group life insurance supplements for deaths in terrorist attacks abroad, and coverage for travel, related expenses, and representation expenses. Members have annual service obligations, including scheduled training and active service. The Secretary can call members to active service without their consent during national emergencies declared by Congress or the President, for limited durations, or for failure to perform obligated service. The President can also authorize calls to augment diplomatic efforts for up to 365 days during emergencies such as attacks on diplomatic facilities, terrorist threats, or natural disasters. Additionally, the Secretary can call members for preplanned missions supporting Department bureaus or embassies, requiring Congressional notification and budget justification. Active service can be performed with or without pay, and active service agreements define service terms. The bill outlines a promotion system based on selection boards, mirroring the Foreign Service. Provisions for retirement include voluntary retirement for members aged 60 with 20 years of service, mandatory retirement at age 65 (with exceptions), and retirement or termination for disability or incapacity. Members may also face retirement or termination due to exceeding maximum time in class, relative performance, or for cause. Corps members participate in the Foreign Service Pension System, with active service counting towards retirement points. The legislation mandates standards and qualifications for retention and promotion, along with periodic compliance determinations and a continuous screening system to ensure a proper balance of skills and readiness. Comprehensive medical and dental assessments are required every six months. The bill also provides for reductions in force and requires readiness exercises at least every two years. A dedicated "Diplomatic Reserve Corps Account" is established in the Treasury for funding salaries, training, operations, and other expenses. Finally, the bill extends employment and reemployment rights under the Uniformed Services Employment and Reemployment Rights Act (USERRA) and protections under the Servicemembers Civil Relief Act to Diplomatic Reserve Corps members during active service.