Perhaps "wing it" is a poor choice of terms. You should really consider how you want to live and how you treat others. Also consider how you'd like to be treated if the roles were reversed. Consider how you and others would be affected if you chose a completely selifsh path. Consider how you and others would be affected if you chose a completely selfless path. Consider your responsibility (if any) to yourself. Consider your responsibility (if any) to society. Then consider how to balance that all together.

I suggest that we each have a responsiblity to take care of our own needs first and foremost (to not become a burden on society). In addition, we need to care for our family or those who depend on us (again, to not burden society). After that, our remaining resources can be split between personal enjoyment (we all need recreation), and giving to society (charity, public works, other selfless acts, etc.).

So here's the scenario. The U.S. should train assassins to kill or otherwise depose world leaders who refuse aid, right? Who is going to decide when and where to use these assassins? Should the U.S. President be able to assassinate world leaders? Currently it is against US policy to assassinate anyone either in the US or abroad, and it may even be against US law (not certain). Perhaps you'd want the UN to be in charge of this, but the UN is supposed to be a diplomatic group resolving matters through diplomacy, not assassination (some will argue that assassination is a tool of diplomacy, but that's a different thread).
Generally speaking, assassination is a Pandora's box that nobody wants opened. If it is legitimate for the US to assassinate leaders of other nations, then it is also legitimate for other nations to assassinate each other's leaders and the leaders of the US. While assassination attempts do occur between nations, they rarely succeed, and they often lead to all out war. Generally speaking nations agree to not use assassination as a sort of unspoken "gentlemens agreement". This allows negotiation to remain somewhat professional instead of becoming personal. Changing that would change how nations deal with each other. Sure the threat may cause someone to change their stance, but it is more likely that you'd end up with national leaders being killed and puppet governments being erected all over the world. This is something that I don't think anyone wants.
A slightly better solution would be a regular military operation to replace an uncooperative nation. Let's say that the US sent troops into a nation that allowed its people to starve. A huge portion of the world would likely be opposed to that action. You'd hear things like "American Imperialism" or "disregard for international law". You'd see the US vilified even more than it currently is.
Currently the world opinion is against the coalition for invading the sovereign nation of Iraq. We all know that Saddam Hussein was a brutal tyrant who killed thousands (maybe millions) of his people during his reign. He used chemical agents against some of his people. He instituted state sanctioned torture and rape. He buried his victims in mass graves without the dignity required by the Muslim faith. Many of his people lived in abject poverty while he lived in luxury and he refused to do anything to help his people, preferring instead to oppose the United Nations and toss out any relief efforts that were made. An overwhelming majority of the world is glad that he's out of power, not the least of which are the Iraqi people, and yet the coalition is vilified for removing him from power. World opinion still opposes the Iraq war regardless of the obvious good that it has produced and will continue to produce. Do you think that they'd be in favor of a war over starvation?
As sad as it seems, it comes down to costs. There is a significant cost to waging war or performing assassinations. The cost is both political and financial. Some would say that no matter how much the cost is, it pales in comparison to even one human life lost to starvation. Consider this then:
If the United States were to expend billions of dollars in a war and lose even more international support, it would risk boycotts and international power. If it loses that power, it loses the ability to help others in the future. Remember when we discussed selfishness and selflessness? I said that one must preserve himself as well as help others. If the US helps others, but loses its ability to preserve itself, then it has lost the balance needed for survival. On a very small scale, if I give so much of my income and time to helping others that I lose the ability to care for my own family, then I have negelected part of my responsibility as a human being and I may very well end up a burden to the very society that I was trying to help. If, instead, I take care of my own family first, and only give from what is left, then I have fulfilled my responsibility (that is to improve society overall). I may not be able to give as much, and not solve every ill, but I have helped somewhat and haven't become a burden to society at the same time. Currently, the US flirts with its world image being damaged. Certainly some people dislike the US, but the intellectually honest still admit that the US, even in invading Iraq, has done much good in Iraq. It is also pretty clear that the US is not doing this to plunder Iraq for its resources which aids its image somewhat. If the US were to start a widespread military campaign against starvation, many would see it as a thinly veiled attempt at empire building. We'd face sanctions and boycotts and the US would suffer, possibly to the point of its own ruin.
Even if the US simply tried to impose influence against another nation to get humanitarian aid to its people, it would be a government dealing with another government. Sovereign governments have several tools of diplomacy, but when governments are at odds, the tools are limited to: negotiations, embargoes, tarriffs, blockades, wars and covert acts. With the exception of negotiation, all of these carry some level of negative connotation and can appear as "bullying tactics" which hurts world opinion of the government in question. Negotiation is positive, but it can take decades to reach an agreement (during which people starve).

A far better solution (you knew I'd eventually get to one) would be to empower non-political groups to tackle humanitarian efforts. Charities (even and perhaps especially religious ones) are more than willing to go into every nation and help out, even in spite of dictators who oppose them. They also aren't going to be seen as an invasion or empire building. Of course charities are not (and cannot be) government funded, so they must be supported by donations. To really make that possible, the average person would have to have more disposable income to give to those charities. Right now, taxes in most nations are so high that charities are underfunded. Even in the US, with its relatively low (yet still too high) tax rates, people don't have the resources to give as much as is needed to charities. Now lower taxes have their own costs and we can get into that later, but the point is that a charity, if properly funded, can handle humanitarian crises much more effectively than a government can and without all of the negatives that government intervention would bring.

-- Jeff

ps We're into several issues now that really deserve their own threads. I'd be happy to see this broken out for more in depth coverage of each and even for more people to get involved with this with their own ideas (if you're reading this, post).

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"Government is not the solution to our problem, government is the problem." --Ronald Reagan