Warning Tier

ELEVATED — sustained. De-escalation did not materialise after Sep 7 or Sep 14. Three formal JCRP designations in September (Sep 5, Sep 9, Sep 17) is without precedent in the 2026 ADIZ reporting series. Tier review: after Sep 24 Xi–Trump summit outcome. Triggers for SEVERE remain: large-scale amphibious rehearsal; CCG inspection zone over Taiwan-bound shipping; four-quadrant encirclement named exercise.

PLA Activity — Sep 15–21

Sep 17: ROC MND issued JCRP press release (PressRelease/87710). 19 sorties — J-16, Su-30, H-6, KJ-500, UAVs. 15–17 of 19 crossed the median line. N, SW, and E ADIZ. Third formal JCRP designation of September; second in eight days. Prior pattern of spike → rapid de-escalation has not held since Sep 9.

Sep 18: PLA military drone entered SW ADIZ; tracked to waters off Taitung County, 0005–0600 local time. Concurrent with President Lai Ching-te's presence at Jioupeng Base (Pingtung) for a final-day inspection of a three-day joint combat readiness exercise simulating air defense interception and long-range strike. ROC MND deployed aircraft, naval vessels, and land-based missiles in response. Source: Taipei Times, 18 Sep.

Sep 18 drone event: PLA demonstrated real-time ISR targeting of the ROC Commander-in-Chief during a named combat readiness drill. First documented instance of a PLA drone shadowing a sitting ROC President at an active exercise.

Sep 19: 20 PLA aircraft, 14 PLAN vessels around Taiwan. 13 aircraft crossed median.

Sep 20: 20 sorties, 7 PLAN vessels, 6 official ships. 15 of 20 crossed median line. N, C, SW, and E ADIZ simultaneously engaged — four-zone coverage without exercise designation.

CCG East-of-Taiwan — Month 4

Continuous CCG deployment since June 2026. Most recent rotation: cutters Putuoshan and Daishan held station 74–105 nm east of Green Island, covering 27,100 sq nm. Daishan/Baita completed their ~30-day cycle; unnamed relief rotation dispatched. Taiwan CGA vessel Chi An shadowing. No inspection zone; no shipping-closure NOTAM. USCC has characterised the formation as contesting Taiwan's eastern maritime "back door" for US/allied logistics and communications. Four months of continuous presence confirms institutionalised patrol calendar.

Xi–Trump Summit — Sep 24

Xi Jinping arrived Washington 21 Sep (Bloomberg; Eastern Herald). Received at Joint Base Andrews — an unusual protocol signal. State dinner 24 Sep evening; attendees include Bezos, Pichai, Altman, Cook, Musk, Jensen Huang.

Confirmed agenda items: trade truce extension (90-day tariff truce expiring), AI safety notification mechanism, rare earths, Iran, Taiwan. Taiwan is third-tier; Heritage Foundation pre-summit briefing (20 Sep) assessed Taiwan will receive minimal dedicated time.

$14B arms package — STATUS PAUSED. Beijing communicated via diplomatic channels that approval before Xi's arrival would cause summit cancellation. Package was not approved pre-arrival. CFR, AEI, FDD, and Center for American Progress all published pre-summit warnings against treating the sale as a negotiating chip. Trump publicly described the package as "a very good negotiating chip" with China (Fox News, post-Beijing May summit).

Foreign Policy (14 Sep): "To Strike a Deal With Xi, Trump Is Killing 'Strategic Ambiguity' Over Taiwan." Charge: Trump allowing Beijing effective veto over US arms decisions for Taiwan, in violation of Reagan's Six Assurances.

Sen. Pete Ricketts (R-NE), 16 Sep: "The United States will not tolerate any change in Taiwan's status by force." Rubio and SFRC bipartisan letter (May 22) reaffirmed Taiwan policy unchanged. House Select Committee (Krishnamoorthi) letter warned against concessions ahead of summit.

Statements — Sep 15–21

Beijing (PRC MFA, 17 Sep): "Taiwan's future must be decided by all 1.4 billion Chinese people, including Taiwan compatriots." Cross-strait dialogue characterised as halted because DPP "rejects the one-China principle."

Taipei (MOFA, 17 Sep): Thanked European Parliament resolution recognising Taiwan's resilience; referenced EUDS Special Committee July 2025 visit.

Polymarket — Sep 20–21

Before 31 Dec 2026: 4% ($42.4M traded — high-liquidity contract, price stable since Aug 27)
Before 30 Sep 2026: 1% ($2.1M)
Before 31 Dec 2027: 11% ($3.1M)

Traders citing: halved air sortie frequency YoY despite JCRP spikes; absence of large-scale amphibious exercises; summit de-escalation premium.

Assessed Probabilities

1 month: 2–4% — summit incentivises short-term PLA restraint; JCRP cadence elevated but below pre-invasion threshold indicators.
6 months: 5–7% — summit outcome will reset or sustain pressure track; arms sale fate is the primary variable.
1 year: 10–13% — structural: PLA 2027 readiness target, Party Congress dynamics, US deterrence signal.
5 years: 18–24% — quarantine/blockade pathway weighted 2–3× invasion within this figure; institutionalised CCG east-of-Taiwan patrol adds to blockade readiness evidence.

Next Inflections

Sep 24: Xi–Trump White House summit — arms sale fate; tier review. Q4 2026: HIMARS delivery on schedule. No date: PORCUPINE Act House floor vote; $14B sale resumption (contingent on summit). 2027: Party Congress; PLA stated readiness target.