I happen to believe in freedom of speech, especially political speech, and if you're not allowed to spend money broadcasting your speech or printing your messages, you don't have much freedom of press or speech.
It is very strange the way that "Libertarians" are so able to turn all rights into property rights. Thus freedom of speech become freedom to have influence on the politicial process in direct proportion to wealth. I began work on the web in '92 because I saw its potential as a political tool which did not have the bias of wealth. It has the potential to create a new kind of political dialogue. When the Web becomes as ubiquitous as the telephone we will still see inequalities of power, the homeless and the poor will still be underrepresented. But that situation must be judged against our own where the political process can be bought and traded as if it were any other form of comodity. It is not simply an issue of money, it is an issue of national security. If a foreigner were to control the majority of the media there would be a significant threat to the national interest. This threat has been realised in the UK with the comming to power of Rupert Murdoch. Fortunately his influence on the US political scene has thus far been minor. In his own country he has brought down the government more than once.
And as far as "prevent the political process from being owned by the rich" goes, there have been brief exceptions over the last 5000 years in which the less-rich have overthrown the rich, but campaign finance laws have almost never kept the rich or the politicians from helping each other out.
In UK politicis the influence of an individual's money is limited to influencing one party. Even that is done behind closed doors. The other major parties both limit the size of individual contributions to a constituency party to a relatively nominal sum. $5000 is a huge sum in UK politics.
I also don't believe freedom of speech should be limited by national boundaries.
Nor do I. But I only vote in one country. If we take the question outside the US it would not on the whole be a good thing if the Prime Minister of Tobago (say) were provided with a campaign contribution of $1M by a foreign company with an interest in strip mining the entire island. similarly it would be a bad thing if Columbian drug lords were to make massive contributions to politicians committed to continuing the prohibition on drugs. Phill