I will define national security fairly broadly, and include the military, intelligence agencies, homeland security, disaster warning, and disaster response.
Constellation gives the following national security benefits:
Ares V heavy lift - Impressive security payloads could be launched by Ares V. However, it's not clear that such expensive heavy lift rockets or their payloads are affordable by security agencies. Also, heavy lift would not be available until about the year 2028.
Partial common hardware with EELVs - This commonality encourages lower cost to security agencies for some EELV components. However, this benefit pales in comparison with the alternative, which is actually using EELVs. Also, significant benefits don't begin until Ares I operations in 2017-2019, and they are still quite minor due to low Ares I flight rates. Only when Ares V becomes operational would this benefit be felt.
Solid rocket support - This advantage seems to be quite indirect and diluted compared to the more straightforward security benefits that come with the new budget.
The new NASA budget gives the following national security benefits:
Space Technology - Many of the investments in this portfolio, such as sensors, robotics, propulsion, materials, small satellites, low-cost access to space, rapid prototyping, and communications, can be expected to benefit the military, intelligence agencies, disaster warning and response, and homeland security. Some of this work will also share launch infrastructure costs with security agencies.
Heavy lift and Propulsion research and development - Research and development into cost-effective heavy lift may provide benefits to the various security interests. If heavy lift is ever to benefit such organizations, it is going to have to become affordable, so investments in affordable heavy lift now seem more useful than starting to build an unaffordable heavy lifter after Ares I is operational. In addition, even if affordable heavy lift doesn't pan out, such R&D results might be applied to other classes of rockets. General propulsion research and in-space engine technology development should also benefit security organizations.
Critical Technology Demonstrations - Some of these demonstrations will be very useful for security agencies. For example, in-orbit propellant transfer would be useful for providing a market for EELVs and new low-cost rockets, lowering their per-unit price. Such technology could also be used to maintain security satellites. The applicability of various demonstrations to security will depend on the individual technology, but many can be expected to be helpful. Some of this work will also share launch infrastructure costs with security agencies.
Commercial Crew and Cargo - The additional cargo funding could bring Falcon 9 and Taurus II rockets online faster, making these rockets available to security agencies. The commercial crew effort would bring more flights to EELV or new low-cost rockets, presenting security agencies savings by sharing infrastructure costs or by availability of new low-cost rockets (or both). This effect could be greater if additional markets for crew transportation are established. In addition, our dependence on the Russian Soyuz for crew rescue since the beginning of the ISS and for crew transportation has been cited as a security liability. The Augustine Committee estimates that Ares I would be ready by 2017-2019, whereas commercial crew would be ready by 2016 at the latest.
Earth and Climate Science - The new missions in this portfolio will allow more cost-sharing with national security rockets. In addition, the satellites and their sensors will allow shared industry support with national security satellites, especially those that observe the Earth (spy satellites, missile warning satellites, natural disaster warning satellites such as NOAA's weather satellites, etc). The new funding for Venture-class Earth science missions may encourage the reusable suborbital rocket and smallsat industries, which will present new opportunities for Operationally Responsive Space and other security functions.
Robotic Precursor Missions - These missions will also share industry support with security agencies for launch vehicles, satellites, and robots.
Aeronautics and Green Aviation - New funding for unmanned vehicles in the national airspace may help broaden this technology used for security.
Full Utilization of the ISS - Closer ties with ISS partners helps certain international relationships which may be advantageous from a security standpoint.
Planetary Science - The new budget restarts plutonium-238 production in support of deep space exploration. Our current dependence on Russia for plutonium-238 has been cited as a weakness, and this budget would begin the long process to remove that weakness. In addition, the Near Earth Object survey is strengthened, delivering a certain sort of security to the Earth.
The security benefits of the new NASA budget seem more numerous, direct, timely, widely applicable, likely to actually happen, and of larger magnitude than their Constellation counterparts.