There is a basic fallacy in your argument, which is that somehow Federal spending is a per-capita phenomenon in the first place. Spending programs need to be looked at on a case-by-case basis.

First, some numbers:

Census Bureau population for 1974: 213,853,928

Census Bureau population for 2000: 281,421,906

Increase: about 32 percent.

http://www.census.gov/population/estimates/nation/popclockest.txt

http://www.census.gov/population/cen2000/tab05.pdf

So how would an increase in population increase Federal spending?

Take an average citizen who is employed in the private sector, a homeowner, and a taxpayer. He does not receive welfare or Social Security. How much does the Federal Government spend on him right now? Defense? Why should it cost more to defend a nation of 281 million people than it would a nation of 213 million people? It wouldn't. Highways? Should mostly be coming from state gas taxes. In fact, increasing the population of such productive people, who pay far more in taxes than they get back, should by all accounts increase the surplus.

So we're not talking about this guy, the average American. Then who? What we are talking about is welfare and other income redistribution schemes. Both the number of programs, and the number of people eligible for them, have increased drastically over this time period.

As just one example, let's examing the elderly, and Social Security. Take a look at this reference.

Note that the number of people getting "income support" has gone from 10.6 percent of the population in 1965 to 27.4 percent in 1998. When you factor in the population increase during this time, the overall number of recipients has skyrocketed. Yet the elderly population has increased from 10 percent of the population in the 1970s, to only 14 percent in 1998.

So where the heck is all the money going? The next figures in the paper are instructive. The amount of Social Security going to the elderly has not gone up that much. The percentage of elderly getting payments has gone from 53 percent in 1965 to 66 percent in 1998. However, the amount of Social Security received by "workforce age" recipients went from 3.2 percent in 1965(!) to 18.4 percent in 1998. The table shows how many new categories were created for Social Security recipients, allowing more and more people to qualify.

Remember, a person totally dependent on Federal funds to live, is for all intents and purposes a slave to the government. It is the fondest wish of the Democratic Party to have every person in American eventually fall into this category. Social Security is one front on this war. Single-Payer Health Care is another front.

I remember the Florida elections, where Democratic Party officials shepherded elderly out of their homes, transported them to election sites, handed them cards telling them how to vote, and shipped them back afterwards. When one such card was misprinted, these hapless voters blindly voted according to the misprint, costing the Democrats many hundreds of votes. Naturally, the Democrats did not wish to widely advertise this fact.