They don't have an obvious foreign power to which they may have pre-existing relationships. They could still be motivated for financial, ego, or ideological rea

They don't have an obvious foreign power to which they may have pre-existing relationships. They could still be motivated for financial, ego, or ideological reasons. USSR/Russia was more often ideologically motivated people (and very small amounts of money). Israeli spying in the US has been "for the benefit of Israel" (and possibly tacitly supported by some of all of USG, potentially somewhat officially). Chinese spying seems to be largely of the "loyalty" form. A lot of it is pure commercial or military technology from commercial entities. All things being equal, someone with minimal foreign relations is going to be a better security risk for USG than someone with extensive relationships with foreign entities. For intelligence aimed at a foreign country, it's obviously an asset to have a lot of interconnectedness with that country, so it's a balancing act; you'd probably be willing to take that risk for a case officer but probably less so for a support staff. For positions where technical skill is required and in short supply, it may be worth that risk too; you'd have to look at the totality of the situation. Since China has such an active intelligence program focused on the US, it's a greater risk than, say, Germany or the UK.