The proposal argument is probably the most common form of argument.  The central task of a proposal argument is simply to propose a solution to a problem.  The problem may be local (What should be done about the terrible parking situation at school?  How may we alleviate the noise pollution in certain parts of town?) or more global (How might the tens of millions of Americans who have no health insurance receive proper medical care?  What are the best ways for the U.S. to deal with terrorism?).  Before one can propose a solution to a problem, though, the arguer must usually provide compelling evidence that the problem exists.  How much explanation is required depends on how well known the problem is and how much the audience knows about the situation.  It won't do to simply proclaim "Save the rainforests!"  The careful arguer must establish an explanation, a context, for the argument.  (This is, of course, true of all arguments.)  Why must the rainforests be saved?  Saved from what?  What are rainforests?  Where are they?  Who is harming them and why?  How can we save them?  The arguer cannot simply assume that the reader knows all about the problem; such an assumption on the part of the writer suggests an ethos of laziness, bad sense, and lack of real concern for the issue.

Having described the problem, the writer must propose a feasible solution to the problem.  The careful writer will not propose a solution without a proper attention to the often harsh realities involved in the actual implementation of the solution.  People are, in ways, naturally conservative.  Few of us see a need to change something if things as they are work sufficiently or if we perceive that the proposed change will make matters worse.  The writer of a proposal essay may find wisdom in the cliché "If it ain't broke, don't fix it."  If one writes a proposal essay about the problem of illiteracy in Arkansas, she might propose that funding be increased for libraries and adult literacy programs.  While these are certainly feasible solutions and (few would disagree) would address the problem, the arguer fails is she doesn't sufficiently address the source of that funding.  Does the writer propose that taxes be increased?  If so, one faces an uphill battle; for "raising taxes" is a (perhaps increasingly) negative concept, something politicians resist doing, lest they confront a barrage of orchestrated protest and the exit door come election time.  If the writer suggests that the funding be donated by businesses, philanthropic organizations, or government agencies, she faces a different sort of uphill battle.  Many of us hate change, sometimes for good reason, so it is the proposal writer's job to take into account the complexity of the situation in his writing.

In most arguments, there is more than one possible solution to a given problem.  If it is fitting--if in doing otherwise it will seem obvious that the writer is, through lack of attention or intent to deceive or simplify, leaving out other, possibly valid solutions--then the writer should address solutions other than his own and disprove or appropriate them.  Facing up to other possible solutions shows that the writer, possessed of a strong ethos, views the situation in its proper light and with a sense of the complexity of the problem.  It is not enough to describe a problem and propose a solution; the proposal writer must also show that his proposal, above all the others, is the best solution to the problem.  Some change, involving pain or inconvenience, may be necessary in order for the solution to be realized, so it is incumbent on the writer to show that the pain is only a temporary state, that it will have been worth enduring in order to experience the greater good of a solved problem.