> civil war

Yes this is overriding factor.

> The US will bomb the shit out of it if they can't keep it

IMO no, this is where the US will bomb TSMC analysis falls short. Including US Army War College analysis that suggest bombing TSMC that started drama. Bluntly TLDR is during wartime, TSMC is a card PRC has, not US.

Incentive wise, it's in overwhelming US interest to keep TSMC tap open. If anything PRC has more incentive to crater TSMC to deny US access to significant % of high end chips that's already denied to PRC - US CHIPS reshoring only projected to capture like 10% of market share in next 10 years, and TBH TW will still retain many sole source semi supply chains that it's questionable if US high end fabs can produce without access to TW supply chain in short/medium term. Overall, US hi tech dependence and IP captures vast % of TW's semi value. Losing access to TW semi hurts US the most. Meanwhile, nothing in US strategic writing indicates attempt to completely rebuild indigenous semi supply chain, something only PRC is pursuing, because none of the CHIPS4 partner would be onboard if they knew US semi strategy is essentially to replace them long term. PRC semi independence is a technical problem, US semi independance is a political / security problem that could potentially undermine it's entire East Asian security posture.

Short/medium term keeping TSMC around is in almost everyones interest. PRC wouldn't mind control but it will still be dependant on western supply chains, US wants continued access because vast segments of their strategic industries depend on it, TW wants fabs around because however war ends, they'll want to retain profitable strategic industry to keep talent and help with recovery. Hence talking point that TW would rig their own fabs to explode even more stupid. Which all points to leaving TSMC alone, if not using it as moderating force in conflict, or more likely something PRC can leverage against US. The reality is US has leverage over export controls / sanctions during peace time, PRC has leverage over cratering US access to TW (really east asian) semi supply chain during war. If indopac goes spicy, one of PRC's trump card is basically resetting most of US/western semi by decades, which pending on how PRC semi industrial policy fares, could actually close the semi gap.

If conflict escalates to TSMC being gone, expect Samsung Semi and Tokyo Electron and most other western semi vendors in East Asia to be gone to. Expect CONUS fabs to stop operating unless US successfully reshores the entire semi supply chain on CONUS, which US partners will fight tooth and nail to stop. And even then there's escalation tier of homeland strikes in a few years that's going constrain US ability to intervene even more. While PRC wants TW for historic sake, preserving/destroying TW (and East Asia) semi decision matrix is going to play major factor in influencing scope of conflict. Which will likely boil down to US conceding TW to PRC without much of fight while PRC concedes to US strengthened security presence in East Asia maintained by unholy cooperation to keep semi spice flowing. Or total war that that covers mainland PRC and US partners in East Asia and CONUS.