1) Papers that argue strongly for one position or another are generally more interesting and engaging than papers that straddle the fence, and/or

2) Papers that argue strongly feed the ego of the professor by making them feel as though the student passionately cares about the assignment

So clearly, it pays to take a strong position in any assigned paper that calls for you to pick sides. The question then becomes "how do I take a strong position?" Beyond that, it becomes "how do I take a strong position and back it up so that it sounds persuasive?" Luckily, it's actually quite easy to do both of these things! As long as you are willing to put in some hard work and keep the following rules in mind, you can be writing strongly argued papers that spark your professor's interest and ego in no time.

Principle #1: A strong position does not mean an arrogant position

Some people confuse having a strong position with being arrogant. This causes them to write as though they are infallibly correct, paying no attention to opposing arguments or even acknowledging that any exist. This is a mistake! A truly strong position can withstand criticism from other viewpoints, and a strong writer makes sure to respectfully address and refute those other viewpoints in his paper. For example, let's say you are arguing in favor of free markets. You must realize that there are alternate theories (like socialism) which have widespread appeal. Keeping this in mind, you would want to acknowledge socialism and point out why the common perceptions of it are wrong or mistaken. This strengthens your point by demonstrating that you have considered other points of view.

Principle #2: A strong position must be supported with evidence

No position is as strong as it could be unless you corroborate it with empirical evidence. To continue our free market example: it is not enough to merely assert that free markets produce more wealth and ensure a better standard of living than socialism does. To make a truly iron-clad case, you would also mention the many studies that have been done on the results of capitalism vs. socialism in various countries, rises and falls in real per-capita incomes, etc. You would explain concrete examples of capitalism's triumphs and socialism's failures in actual cities, towns, and countries throughout history. Such supporting evidence makes any position stronger and more credible.

Principle #3: A strong position must be supported with bold, decisive language

Of course, once you have taken other points of view into account and gathered corroborating evidence, you also need strong language. Here are some phrases that will make you sound very confident of the position you've taken:

"Taking this into account, it's difficult to conclude anything other than [your position here.]"

"To think [the opposite of your position] would be a dangerous lapse into wishful thinking."

"Clearly, an overwhelming body of evidence and the consensus of experts suggests [your position]."

Don't overdo it on these; rather, simply use them where they seem to fit best, in places where they will give your paper an air of declarative power. Keep these 3 principles in mind and you should be on your way to writing strongly argued papers in no time!