Intervention means quite simply, sending troops into another country, under whatever pretext or excuse.  From the point of view of the affected country, it usually looks like an invasion is happening.The most outrageous intervention in recent history was the war in Vietnam.   I was against this, to the extent of being jailed in Montreal for demonstrating against it.  Some supported it, however, among them those who felt this their Christian duty because of their understanding of Romans 13 -
"Every person is to be in subjection to the governing authorities. For there is no authority except from God, and those which exist are established by God."  
According to this view, protesting against the actions of the US government was wrong, because one should be in subjection to the governing authorities.
I have come to see that this interpretation is completely backwards.  While in St. Paul's time the governing authorities meant the Romans, meant the government of one's own country, today the UN has 193 member states.  Whatever their political persuasion, they have all be established by God, for government is a good thing, and all good things have been created by God. 
Therefore, in the modern world, a Christian who finds himself in a foreign country should be in subjection to the governing authorities of the country he is visiting.   He/she should not be training and arming dissidents, fomenting revolution, or even worse, planning and carrying out military invasions including bombing civilians and civilian sites.  But all this has been carried out, by purportedly Christian people, most recently in Libya where thousands of people including their head of government were killed; and is now being contemplated for Syria and Iran. 
I t is ironic that many justified the slaughter of the Vietnamese by the domino theory, the notion that the war was preventing the Chinese revolution from spreading.  Ironic because from ancient times the Chinese have always practiced non-intervention, preferring to build relationships through trade; and this practice of non-inhas been the hallmark of the current government's foreign policy.