Intel is the only US based and owned foundry that is on the leading edge of fab process technology. That's what the government wants domestically. Defense isn't just military and certain intelligence and similar functions need high performance hardware. I somehow don't think the NSA is using CPUs made on Northrop Grumman's 180 nm planar CMOS process. Army radios might use that shit but the highest tech defense and intelligence agencies are using modern hardware. Intel is the best option for manufacturing it.

TSMC could be an option now with its US based GIGAFABs but it would be a much more complex deal with the US government where chips made for it would have to be made entirely in the US and possibly by a US domiciled subsidiary instead of TSMC's main Taiwan based parent company. The same goes for Samsung.