If I was a foreign power looking to exert power over the US I would want to disable the US ability to stop me from exerting that power. Read this and see if you can think of a better way than destroying the career of a whole generation of FBI agents and hurting the ability of the FBI to recruit top talent for the next generation.
Agents continue to work cases, but O’Connor said that the shutdown “is slowing F.B.I. investigations, and it will only get worse as it drags on.” Field offices in New York, Dallas, and Newark have set up improvised food banks as well. Employees are walking into their supervisors’ offices in tears and asking for help. Others fear that they will be unable to make payments that are due and potentially fail one of the Bureau’s routine financial-background checks, which could cause them to lose their security clearance and, with it, their job.
Source: For a Besieged F.B.I., the Shutdown is the Latest Trump-Era Assault | The New Yorker