You're saying that the "ends justify the means." But if so, where does that end? Murder is justified, as long as it clears the way for public property; slavery is justified if those enslaved fight for the country(how do you feel about drafts? If you disagree with them, you contradict yourself); theft is justified if it is done for the "public good." What is the public? Is it everybody within a specific area? But not everybody uses a new road, or a new bridge. Then what is it? Is it some undefinable, intangible body over the individuals? If you can't define the term, how does the phrase "public good" even have any meaning? "This is done for JKSGDUF398DSFS!#." Does that make any more or less sense?
The "public" is merely a collection of individuals. Check the "needs of the masses vs. the needs of the individual" in EoEO - that thread supports pretty much everything I've said here. If the public is merely a collection of individuals, then the "good of the public" must be in the best interest of every individual. The only common interest every individual has is freedom. Therefore, logically, the only moral purpose for the government is to ensure freedom for everybody - by the exclusion of the initiation of force from human relationships. The logical conclusion of freedom is that no person has the right to initiate the use of force - this includes the government. Only retalitory force(self-defense, throwing someone in jail) is acceptable.
Force and freedom are opposites. Once a government legalizes the initation of force to seize private property by subjective whim(for the good of the undefinable "public") or to steal private income by equally subjective whim, it loses any right to proclaim freedom - it becomes a dictatorship. Such was evolution of Soviet Russia and other communist nations.
If the government was limited back to its only moral purpose - to protect individual rights, then it wouldn't need all this looted money from the people, and could go without income tax entirely - if necessary, resorting to other means of fund-raising(other means of taxation not based on income, charities, etc.). Also, those areas bereft of public funds, may even benefit from privitization. Privitization encourages competition, and competition encourages development - in a free nation. Such is the sound principle of capitalism. Note that in the 19th and early 20th centuries, the degree of freedom of a country was proportional to its economic, industrial, and technological growth. The United States, by far the freest, achieved the most. Now, ever since the introduction of the welfare state, the degree of freedom is lowering, and the US is losing its standing as the industrial powerhouse. Not to say that the US is not the freest country(which it is) or probably still the leading economic, technological, and industrial nation(which it probably is in every respect) - but that it doesn't have such a huge lead anymore. With public education, public welfare, public social security - things are stagnating. This is no coincidence.
Freedom and force cannot coexist. I cannot go up to my neighbor, take out a gun, and demand he hand over his income or his property; why can the government do so to me? When a government claims a right on the life of every person in it, it turns from a free government to a dictatorship - ruler by force. There can be no compromise where freedom - the right to your life - is concerned.