Public sector funding is typically incremental, for one year or two if you're lucky, and subject to the seeming whims of the politics of the moment, to say nothing of the economy that is supposed to source the funds.
What's a PMO supposed to do?
The mainstream risk mitigations for incremental funding is planning in waves, and constructing project and product architectures that accommodate boundaries and deliverables that conform to the budget cycle.
Boundaries means respect for interfaces: that is, in order to get some degree of boundary definition, scope is compartmentalized, and entry/exit is through defined interfaces. In the software business, it's common to think of objects, each object's functionality accessed through an "API" -- application programming interface.
Such a strategy then begets some protocol for ICDs: interface control documentation/design/definition (pick your "D" word)
Another possibility is to plan with options. An option strategy requires a small down payment -- usually not refundable -- to protect future decisions. Recall Yogi Berra's strategy: "If you come to a fork in the road, take it!"
Check out these books I've written in the library at Square Peg Consulting
