quote:

"The Army WO is a self–aware and adaptive technical expert, combat leader, trainer, and advisor. Through progressive levels of expertise in assignments, training, and education, the WO administers, manages, maintains, operates, and integrates Army systems and equipment across the full spectrum of Army operations. Warrant Officers are innovative integrators of emerging technologies, dynamic teachers, confident warfighters, and developers of specialized teams of soldiers. They support a wide range of Army missions throughout their career. Warrant officers in the Army are accessed with specific levels of technical ability. They refine their technical expertise and develop their leadership and management skills through tiered progressive assignment and education."
(DA Pamphlet 600-3, p. 3-9)

Further clarification of the role of a warrant officer is found in Field Manuals 6-22:

“Warrant officers possess a high degree of specialization in a particular field in contrast to the more general assignment pattern of other commissioned officers. Warrant officers command aircraft, maritime vessels, special units, and task organized operational elements. In a wide variety of units and headquarters specialties, warrants provide quality advice, counsel, and solutions to support their unit or organization. They operate, maintain, administer, and manage the Army‘s equipment, support activities, and technical systems. Warrant officers are competent and confident warriors, innovative integrators of emerging technologies, dynamic teachers, and developers of specialized teams of Soldiers. Their extensive professional experience and technical knowledge qualifies warrant officers as invaluable role models and mentors for junior officers and NCOs.” (Fm 6-22, p. 3-12)

Additional expectations are shown in Field Manual 7-0.

Warrant officers must be technically and tactically focused and able to perform the primary duties of technical leader, advisor, and commander. Through progressive levels of expertise in assignments, training, and education, warrant officers perform these duties during all operations and at all levels of command. While their primary duties are those of a technical and tactical leader, warrant officers also provide training and leader development guidance, assistance, and supervision. Warrant officers provide leader development, mentorship, and counsel to other warrant officers, officers, NCOs, and Army civilians. Warrant officers lead and train functional sections, teams, or crews. Finally, they serve as critical advisors to commanders in conducting organizational training. (FM 7-0, p. 4-22)

The Army Warrant Officer Corps is comprised of over 25,000 men and women of the active Army and reserve components. Warrant officers are technical experts that manage and maintain increasingly complex battlefield systems. They enhance the Army's ability to defend our national interests, and to fight and win our nations wars.

Candidates who successfully complete Warrant Officer Candidate School are appointed in the grade of Warrant Officer One. When promoted to Chief Warrant Officer Two, warrant officers are commissioned by the President and have the same legal status as their traditional commissioned officer counterparts. However, warrant officers remain single-specialty officers whose career track is oriented towards progressing within their career field rather than focusing on increased levels of command and staff duty positions.