From the document:

Beijing presents a challenge to American interests across the domains of national power, but the military threat that it poses is especially acute and significant. China is undertaking a historic military buildup that includes increasing capability for power projection not only in its own region, but also far beyond as well as a dramatic expansion of its nuclear forces that could result in a nuclear force that matches or exceeds America’s own nuclear arsenal.

U.S. defense strategy must identify China unequivocally as the top priority for U.S. defense planning while modernizing and expanding the U.S. nuclear arsenal and sustaining an efficient and effective counterterrorism enterprise.

China is pursuing a strategic breakout of its nuclear forces, significantly shifting the nuclear balance and forcing the U.S. to learn how to deter two nuclear peer competitors (China and Russia) simultaneously for the first time in its history.

China and Russia, in addition to their vast and growing ballistic missile inventories, are deploying new hypersonic glide vehicles and investing in new ground-launched, air-launched, and sea-launched cruise missiles that uniquely challenge the United States in different domains.

Here’s what Project 2025 has to say about missile defense:

Despite its deterrence and damage-limitation benefits, opponents argue incorrectly that U.S. missile defense is destabilizing because it threatens Russian and Chinese second- strike capabilities.

• Reject claims made by the Left that missile defense is destabilizing while acknowledging that Russia and China are developing their own advanced missile defense systems. 

• Commit to keeping homeland missile defense off the table in any arms control negotiations with Russia and China.

Strengthen homeland ballistic missile defense. The United States currently deploys 44 Ground-Based Interceptors (GBIs) as part of its Ground-based Midcourse Defense (GMD) system to defend the homeland against North Korea, but as North Korea improves its missile program, this system is at risk of falling behind the threat.

• Buy at least 64 of the Next Generation Interceptor (NGI), which is more advanced than the GBI, for an eventual uniform fleet of interceptors. The Biden Administration currently plans to buy only 20.

• Consider additional steps to strengthen the GMD system such as a layered missile defense or a third interceptor site on the East Coast.

Increase the development of regional missile defense. As the Ukraine conflict amply demonstrates, U.S. regional missile defense capabilities are very limited. The United States has been unable to supply our partners reliably with any capabilities, and the number and types of regional missile defense platforms are less than the U.S. needs for its own defense. The U.S. should prioritize procurement of more regional defense systems such as Theater High Altitude Area Defense (THAAD), Standard Missile-3, and Patriot missiles.

Change U.S. missile defense policy. Historically, the U.S. has chosen to rely solely on deterrence to address the Russian and Chinese ballistic missile threat to the homeland and to use homeland missile defense only against rogue nations.

1. Abandon the existing policy of not defending the homeland against Russian and Chinese ballistic missiles and focus on how to improve defense as the Russian and Chinese missile threats increase at an unprecedented rate.
2. Invest in future advanced missile defense technologies like directed energy or space-based missile defense that could defend against more numerous missile threats.

Missile defense is a critical component of the U.S. national security architecture. It can help to deter attack by instilling doubt that an attack will work as intended, take adversary “cheap shots” off the table, and limit the perceived value of mis- siles as tools of coercion. It also allows space for diplomacy during a crisis and can protect U.S. and allied forces, critical assets, and populations if deterrence fails. Adversaries are relying increasingly on missiles to achieve their aims.

Change U.S. missile defense policy. Historically, the U.S. has chosen to rely solely on deterrence to address the Russian and Chinese ballistic missile threat to the homeland and to use homeland missile defense only against rogue nations.

1. Abandon the existing policy of not defending the homeland against Russian and Chinese ballistic missiles and focus on how to improve defense as the Russian and Chinese missile threats increase at an unprecedented rate.
2. Invest in future advanced missile defense technologies like directed energy or space-based missile defense that could defend against more numerous missile threats.