pohnpei's answer may be misleading on a couple of points, neither one of which refutes the underlying message. Lest the individual asking the question use the examples provided, however, some clarification is in order.
Canada does, in fact, have serious security concerns regarding the United States. It has long felt uncomfortable being tied geographically and geopolitically to its larger, more powerful neighbor. During the Cold War, its security was closely coordinated with the United States because it understood that a war between the United States and the Soviet Union would involve Canada by virtue of its geographical proximity to the U.S. Soviet missiles and bombers would have overflown Canadian airspace, and the fall-out from some nuclear detonations could have contaminated Canadian soil and air. More actively, Canada has long resented the U.S. Navy's submarine patrols through Canadian territorial waters. American submarines have long transited through the Northwest Passage, which Canada claims as its own, but which the U.S. views as international waters. As Arctic ice melts as a result of global climate change, tensions between the U.S. and Canada have grown. Intense competition among the U.S., Canada, Russia, and other Arctic countries for access to mineral and oil deposits in that region have increased the tensions between the North American neighbors.
With respect to China, the issue is considerably more complicated than how the U.S. views Chinese military modernization programs. China claims the entire South China Sea as its own territory, much to the consternation of every other country in the region, including Vietnam, Thailand, Indonesia, and the Philippines. The United States has tried to remain neutral, but has security agreements with the Philippiness, Thailand, and Japan, which means conflicts involving those countries and China will draw in the U.S. Similarly, Chinese-Japanese disputes over the Senkaku Island chain (Diaoyu in China), which does not directly affect the U.S., does require U.S. engagement because of the U.S. defense treaty with Japan. Finally, Chinese military modernization is oriented heavily towards being able to prevent the United States from coming to the defense of Taiwan, should China follow through on its threats to invade that island nation if its asserts its independence too strongly.
In short, students should be cautious in how they use examples to buttress their arguments.
Different students of international relations have different views on this question. My own view is that the security dilemma cannot be completely overcome.
The term “security dilemma” refers to a problem that countries face when they try to make themselves more secure. When a country feels that it is not secure, it will typically try to make itself stronger. By making itself stronger, it feels, it can make it less likely that other countries will attack it. But this action is also problematic. When Country A makes itself stronger, Country B (and other countries) may well feel threatened. Country B will then be more likely to make itself stronger and will be more likely to come into conflict with Country A. Thus, by trying to make itself more secure, Country A may actually be making itself less secure.
As long as countries do not completely trust each other, this dilemma cannot be overcome. It can be overcome when countries trust each other. For example, Canada is unlikely to feel threatened by anything that the US does in terms of a military buildup. However, when trust is less complete, the security dilemma exists. This can be seen, for example, in the relationship between the US and China. We are not enemies, but yet we tend to react to things like the Chinese acquisition of an aircraft carrier. We do not trust them and so we react to their attempts to make themselves feel more secure.
Thus, this dilemma can be overcome if nations trust one another. However, it seems unlikely that we will ever reach a state in which all countries trust one another completely.