Battles loom over nuclear spending.

* A lack of sufficient funds for nuclear modernization will lead to budget battles among and within the services, according to defense analysts.

In a report released earlier this year, the Congressional Budget Office estimated that the Defense Department will need $227 billion over the next decade to carry out its plans for upgrading its nuclear forces, which comprises land-based intercontinental ballistic missiles, ballistic missile submarines and long-range bombers.

The bipartisan National Defense Panel last year called the military's nuclear modernization plans--projected to cost as much as $1 trillion over the next 30 years--"unaffordable."

The financial problem becomes particularly acute in the early 2020s, when the Navy's Ohio-replacement submarine is expected to go into production.

Frank Kendall, the under secretary of defense for acquisition, technology and logistics, has said that the Pentagon's annual nuclear modernization tab will be $10 billion to $12 billion above projected budget levels beginning in 2021.

Unless Congress fills the projected budget gaps, the Defense Department will have to make tradeoffs when it comes to investing in the nuclear portfolio and conventional forces, according to experts.

Mackenzie Eaglan, a defense analyst at the American Enterprise Institute, said inter-service rivalry for available nuclear funds would be "inevitable," especially if the Navy and...