While link campaigning, is getting links from non-US sites pointless if we are not targeting non-US markets? More specific, is the link juice received from non-US sites impact our rankings on google.com? i.e. if we pick-up a link from a co.uk site that ranks well on google.co.uk but not google.com pass any value to us looking to rank well on google.com?
If you are targeting the U.S., then it is probably best to get a large majority of its backlinks from U.S. based sites. But a few links from non-U.S. sites probably wouldn't do any harm, and could even help a little, since they would make the overall backlink profile look more natural. In my opinion the most important criterion for any particular backlink is that it come from a page with relevant content.