The federal budget is usually viewed in big, bold, billion-dollar terms, but its fine print tells a story, too, of the people, policies, and politics that shape the government:

Remember energy conservation? And doing something about illegal immigration? And pork-barrel water projects? Budgets, it turns out, don't have long memories.

Energy conservation, a big goal at the start of the administration, merited $671 million last year but $555 million this year. Another big goal was to stem the tide of illegal aliens, partly by doubling the size of the 2,200-member Border Patrol. It's been two years, and, if this year's budget goes through as proposed, the administration will have 2,300 patrollers by the end of the year. As for water projects, they are alive and well at the Bureau of Reclamation, which is slated for an increase of $170 million over its 1979 budget of $582 million for water projects in 17 western states.

A promise kept:$590 million to study and develop breeder reactors is tucked away in the budget, carrying out the commitment the administration made to Sen. James A. McClure (R-Idaho) to win his vote for the natural gas compromise last year.

Despite government economists' concern over the impact on inflation of federal regulations, regulations are firmly rooted in the budget -- and in some cases expanding. To carry out the 1976 Toxic Substances Control Act, funding would nearly double: from $58.9 million to $103.3 million, with 167 new persons added to oversee the testing and review of up to 65,000 existing chemicals (growing by 1,000 a year) produced by 115,000 companies.

Health, Education and Welfare Secretary Joseph A. Califano's crusade against smoking got two puffs from the budget: an increase in spending for antismoking programs and a cutback in research money for the tobacco industry. Federal spending to discourage smoking would rise from $29 million to $55 million, while money for tobacco research would be cut from $5.1 million to $3.9 million. The reduction corresponds to the amount of money, about $1 million, that the government believes to be used, contrary to congressional directives, in promoting production instead of health.

The president can say no to Cabinet secretaries, governors and mayors, union leaders and the military brass -- but can he say no to his wife? While many health programs failed to keep pace with infltaionary cost increases, mental health, Rosalynn Carter's main area of interest, came through quite well indeed. Money authorized for mental health services, research and training rose from $542 million to $597 million -- roughly 10 percent.

Not all of the Carter extended family fared so well, however. Adm. H. G. Rickover, the nuclear submarine champion and old Navy mentor who inspired the president to ask, "Why Not the Best?", will find that the Department of Energy's Naval Reactors Development programs have been cut back from $297 million to $278 million.

Some hesitant steps toward return of the draft or national service are being proposed for fiscal 1980.

The Selective Service System is seeking $9.8 million, an additional $2.5 million or a 40 percent increase from the current year. Most of that money would be used to hire additional employes to build up an organization that could quickly begin registration of the nation's youth if it were needed again.

More interesting is request in the 1979 supplemental appropriations bill by ACTION, the agency that runs Vista at home and the Peace Corps overseas. A portion of $4 million ACTION wants is to be used for "research into the concept of a national youth service."

Inflation has hit the Pentagon in one highly visible way. The new budget asks that the reward for turning in a deserter or AWOL member of the armed forces be raised from $25 to $75.

Gas rationing is on the administration's mind.

As part of its supplemental fiscal 1979 requests, the administration is asking for $24.6 million to prepare a gas rationing program ready to go into operation on 90-day notice.

The plan will be sent to Congress this year. The funds would be used to print the ration coupons and checks and to develop distribution and recoupment systems and the management programs.

A ration plan already exists, but it was created in the Ford administration and only has been modified on paper by Carter's Energy Department.

Cities may not have received what they wanted from the budget, but they can take solace in the fact that urban recreation is the big focus of the Interior Department's parks budget. The Fish and Wildlife Service budget is cut by about 10 percent to $408 million, meaning less for wildlife refuges, while $187 million is put aside for rejuvenating city recreation facilities.

The 28-year-old Renegotiation Board may be born again, thanks to the Carter administration.

Congress last year passed legislation that terminated the board as of March 31, and gave it only enough money to run to that date. The Carter budget has come back to include a fiscal 1979 supplemental request that gives the board $1.1 million for operations through the end of 1979, and adds language that rescinds the provisions of present law to end its operations.

Furthermore, the Carter administration is asking for an additional $1 million over the current budget for expanded board activities next year.

Among the obituary notices in the budget were these:

The 18-year-old U.S. Travel Service, which spent $14.2 million this year out of offices in London, Paris, Toronto, Mexico City, Frankfurt and Tokyo, will go out of existence -- largely because, the government feels, the tourism industry is healthy enough to do its own promotion.

The Federal Commission on Paperwork fades into oblivion, its ledgers showing it spent, among other things. $91,000 on printing and reproduction costs.

One cut buried in the Defense Department budget is bound to cause a big fight. The National Board for the Promotion of Rifle Practice operates out of the Pentagon and works hand-in-glove with the National Rifle Association in promoting civilian interest in markmanship.

It has been an aid to the gun lobby groups that are opposed to any form of federal licensing legislation.

According to the Carter budget, the board, which costs $375,000 a year and has 13 employes, "will be disestablished by the end of 1979."

Chances are slim that this Carter proposal will get through Capitol Hill.

College loans and government jobs for the unemployed will be subjects of attention to prevent misuse of funds. HEW plans to insist on repayment of student loans, one out of six of which are now in default. Also, the Labor Department plans to hire 37 criminal investigators to work under a new inspector general to deal with abuse of federal jobs programs.

Remember the little amendment Congress passed that permitted "qualified political committees," specifically the Republican and Democratic national and congressional committees, to mail at the special bulk thirdclass rate normally reserved for nonprofit organizations?

The bill for that amendment is now in for the 1978 election year and it totals a startling $18 million. The administration is seeking that amount in a supplemental 1979 appropriation to pay the Postal Service "to offset the loss in regular rate revenues."

Money for basic research will rise by roughly 9 percent to $4.6 billion. This would fulfill Carter's promise to emphasize federal support to basic research. Proposed funding for all research and development efforts, scattered through 29 departments and agencies, is up by $1.2 billion, or just over 4 percent, for a government wide total of $30.6 billion.