Frank Patrick wrote an excellent article about the importance of tying project management to the organization strategy. This also reflects strongly the opinions expressed in Kendall & Rollin's Advanced Project Portfolio Management and the PMO (project management office) that I reviewed.
Enterprise PM - It Starts with Strategic Interdependence
An effective strategic roadmap serves several purposes. It identifies the things that are currently blocking desired levels of attainment of "goal stuff" and tactical objectives designed to get there. Once short- or mid-term problems or blockages are dealt with, the strategic roadmap also lays out a clear vision that builds upon the future freed up capabilities and defines the path to strategic objectives.