In choosing youthful Bud Scruggs, 31, as his new chief of staff, Gov. Norm Bangerter surprised some observers this week. Several other experienced names in state government had been rumored as possibilities for the demanding job.

In addition to a witty and amiable personality, Scruggs is a lawyer and managed the re-election campaigns of both Utah Republican senators, Jake Garn and Orrin Hatch. His legal background may be particularly useful to the governor, the first chief executive in 20 years who hasn't been a lawyer.Scruggs is the third chief of staff named by Bangerter and faces some formidable challenges. It's up to him to see that the governor is well-informed on a dizzying variety of issues, that the chief executive doesn't stub his toe, that policies, budgets, appointments, speeches, and activities are woven into a coherent, manageable pattern.

One big and particularly urgent challenge for Scruggs is helping the administration put the finishing touches on the governor's 1990 fiscal budget - due to be presented to the legislative fiscal analyst in less than two weeks.

That budget must deal with state agencies that have functioned under financial shortfalls and financial restraints for several years, with growing needs in education, and with a narrowly-averted taxpayer revolt still fresh on everyone's mind - a revolt that nearly cost Bangerter his re-election bid.

An improving state economy is expected to produce an additional $84 million next year, but the pleas from heads of state agencies already total more than twice that. And the governor is still mulling over the possibility of some sort of tax cut.

All of this is going to make budget-drafting a painful exercise. Scruggs will head the governor's team as they hammer out the final figures for presentation to the Legislature.

The new chief of staff will not have a chance to leisurely settle in. The very nature of the post is one of pressure, crisis, and constant demands. But the effectiveness of the governor's office will rest in large measure on how well he performs.