International law is stuck in a morass of contested doctrinal description. Its content, effect, and very existence are grist for incessant academic debate and political wrangling.(Warning note by Eagle1: The cited article is written in what I assume to be some sort of "intellectual" languange that smacks of the sociology "we are really a science" stuff I read as an undergraduate. The concept of a simple declarative sentence using simple but appropriate words seems to have been lost somewhere in the groves of academe.)
Not surprising, really, nation states, like the human beings that comprise them, tend to cooperate when it's in their interest to cooperate and not otherwise. Thus, some international things are easy - passports, visas, certain aspects of maritime merchantile and shipping law, trade agreements, etc. Some things are hard- weapons control, international criminal courts, etc. Easy or hard seems to my jaundiced eye to depend on how much control (freedom to act) of its national interests any nation is being asked to cede to some alleged "higher" authority.
So, it is relatively easy for a nation like "Grand Fenwick" to agree to eliminate nuclear weapons, as they never had them and never will. However, to demand that the U.S. eliminate nuclear weapons during the height of the Cold War was to ask the U.S. to abandon a major part of its defense strategy. It wasn't going to happen.
Which gets me to my main point: no "law" - international or not - is effective unless it can be enforced.
There are plenty of articles, books and internet sites devoted to pointing out laws that forbid or require some activity that to our modern minds seem silly but that are still on the books but either are not enforced or cannot be enforced.
In the Admiralty law context, there are many forms of generally accepted terms for inclusion into a contract to engage the use of a ship (a "charter party"). These terms include the duration of the charter and penalties for its breach. They also include, usually, a specification of where a suit can be brought to enforce the agreement. Why be specific? It is hard won wisdom that the legal system of the Duchy of Grand Fenwick may not be as fair and just in handling cases brought for or against its own subjects as might some neutral court or arbitrators. Commerce abhors such inconsistency and the resultant uncertainty. It avoids it by sticking with known forums.
In matters of war and peace, enforcement of treaties, sanctions and other results of diplomacy depend on two factors:
(1)The consent of the party in violation to concede any violation and the willingness of that party to take corrective action as required, or
(2) In the absence of such consent the willingness and ability of the other parties to the treaties, etc, to take necessary actions to force the violator to consent or to remove the violator's government and replace it with a government willing to cease the violation(s).
When President Bush went to the UN regarding Iraq, he first sought the UN's help in getting Iraq to comply with existing agreements and sanctions. He asserted that failure to act would put into question the rationale for the continued existence of the UN. When the UN proved unable or unwilling to act to enforce it own resolutions, he and a group of other nations undertook the enforcement themselves, not in derogation of the UN, it seems to me, but in its defense.
Senator Kerry wants to reverse that process and adopt the idea that even a completely toothless UN is better than one that has member states willing to enforce its resolutions.
Sometimes in looking at the U.S. role with the UN, I am reminded of the movie High Noon. It becomes well-known in a community that a collection of "bad guys" is getting ready to roll into town and cause trouble. The sheriff learns of the plot and seeks the assistance of the town people. Despite their occasional muted indications of support eventually they all fail the sheriff - they all feel they "have too much to lose" or perhaps it's "the wrong fight at the wrong time." The sheriff is conflicted but chooses his "duty" over other considerations. When he has vanquished the evil-doers and the town people belatedly offer their congratulations, he throws his badge in the dirt and rides off. His honor is intact.
Update: Fixed some typos...