Mark Weisbrot gets all of this almost exactly wrong. His argument is that all of Latin America sees Fernando Lugo's removal as a threat to the region, but it occurred because of U.S. influence.
The US has lost most of its influence in the vast majority of the Americas over the past decade. It is only a matter of time before even poor countries like Honduras and Paraguay gain their rights to democracy and self-determination.
If you want to blame an international actor, then you would need to point much more at Brazil. The U.S. does not care about Paraguay. U.S.-Paraguayan relations were not strained (for example, see this very complimentary Congressional Research Service report from 2010), and it makes no difference to the U.S. who is in power (remember that there were even periodic flaps with Colorado president Nicanor Duarte). The impeachment and removal had enough of a democratic veneer for the U.S. to ignore it. Unless you believe conspiracy theories about George W. Bush buying land in Paraguay to escape just like Nazis did in Argentina, in which case I can't help you.
But Brazil is a different story. It wields much more clout than the United States in Paraguay, and had the opportunity to act quickly and decisively. Instead, Dilma Rousseff made clear from the beginning that she would wait and see, then ultimately helped insure that Mercosur did not impose sanctions. In other words, in practice her response was not much different from Barack Obama even if her rhetoric was more pro-democracy. The irony is that Weisbrot makes a point about the decreased influence of the U.S., while not seeing the implication that it has led to more Brazilian influence. And the PT is not committed to democracy abroad, so the reduction of U.S. influence does not necessarily mean more democracy.
I understand the natural instinct to look toward Washington, but doing so exclusively means losing sight of critical regional changes. If we want to understand the future of democracy in Latin America, then we need to probe how far Latin American governments are willing to sacrifice to make it work.