In an era of globalization with borders becoming increasingly porous and sovereignty decreasing, are the standards for interventions that seek to preserve sovereignty becoming less rigorous?

A decrease in sovereignty is often difficult to measure. It was always a matter of more or less (which means, this state had more, this other one had less). It was always limited in ways that theorists and lawyers, focused on the state as an ideal type, failed to recognize. I do not know of any moral philosopher or political theorist who ever argued that states had a sovereign right to massacre their inhabitants (or anyone else, for that matter). In late 19th and early 20th century law books, there is already a recognition of a right of humanitarian intervention. If some of us now argue for an obligation, I do not think that reflects some utterly new doctrine of sovereignty.

But there is a sense in which the practice of humanitarian intervention aims to turn the decrease in sovereignty into an increase. One of the major causes of pandemic violence in the world today is state failure. It turns out that it was Thomas Hobbes who got anarchy right, not the Anarchists. And so when someone intervenes in a place like Sierra Leone, the goal is to create a political agency that can maintain law and order and provide basic services. In the absence of global institutions that work, people need a state. Or, since that word seems to make people on the liberal left nervous, they need the functional equivalent of a state. That is not only true of people who literally do not have a state; it is also true of the much greater number of people who do not have a decent or effective state.

How should a priori state sovereignties be balanced when states seek to counteract the actions of non-state actors?

I assume that the non-state actors that you want to counter are terrorist organizations; you are not after Human Rights Watch or Doctors Without Borders. I would define a terrorist organization as one that is committed, as a matter of policy, to the killing of innocent people. Of course, terror is a means, not an end, so these organizations have other commitments as well. But the strategy one chooses is often morally defining, as in the case of Murder Incorporated, say, or the Mafia, whose long-term goals were and are entirely acceptable in capitalist societies. So terrorist organizations are morally defined by their means, whatever their ends. It is a good idea to counter them.

We might best begin thinking about how to do that with a distinction between states that are active partners of terrorist organizations and states that harbor them. The Taliban regime in Afghanistan was an active partner, and that is why, in the aftermath of the attacks of September 11, 2001, a war aimed at overthrowing the regime was justified. Afghan sovereignty was not a moral impediment. Syria is probably a good example of a state that harbors terrorist organizations: they can establish offices there, hold meetings, publish pamphlets, raise money. It seems to me that the right response in cases like that involves measures short of war, which are likely to be most effective if they are organized multilaterally. In fact, it should be a goal of US foreign policy to mobilize international support for diplomatic, political, and economic pressure on states that allow terrorist organizations to work from their territory.