US President Barack Obama released his fiscal year 2015 budget request to Congress on Tuesday.

The annual ritual highlights his policy priorities for the coming year and serves as a Democratic Party manifesto as Democrats seek to draw a contrast with Republicans ahead of congressional elections in November.

The budget plan covers less than a third of the approximately $3.5 trillion the government is likely to spend next year. The rest will be doled out automatically through federal benefits programs that mostly care for the elderly and poor, including Social Security, Medicare and Medicaid.

Obama outlined how he would parcel out $1.014 trillion on government agencies' discretionary programs ranging from the military to national parks.

The level, barely above this year's spending cap of $1.012 trillion, was set by a recent budget deal and forces Obama to make some difficult cuts to fund the programs he wants. If the president wants to spend more, he will have to sell Congress on the idea of raising additional revenues.

The following are some of president's spending and tax proposals:

Defense spending

The president wants to shrink the US Army to its lowest level since before World War Two, eliminate the popular A-10 aircraft and reduce military benefits. The Pentagon's budget for the 2015 fiscal year beginning in October is an estimated $496 billion, about the same amount as the current fiscal year.

Diplomacy and foreign aid

The Obama administration requested $46.22 billion to fund its diplomacy and foreign aid for fiscal 2015, a drop from this year's estimated $46.81 billion, largely reflecting reduced spending in Afghanistan, Pakistan and Iraq.

The underlying base budget for the State Department and Agency for International Development will hold roughly steady at $40.3 billion for fiscal 2015, which begins on October 1, from the estimated level in the current fiscal year ending September 30.

But the budget for "Overseas Contingency Operations" - funds set aside for exceptional needs - will drop to $5.91 billion from an estimated $6.52 billion, chiefly because of declines in spending on Afghanistan, Iraq and Pakistan, a State Department official told reporters on condition of anonymity.

Transportation projects

Obama wants a four-year, $302 billion plan to repair deteriorating roads and bridges and fund transit projects. He has said he would raise $150 billion in new money by ending some tax breaks for businesses as part of a corporate tax reform that would also lower tax rates.

Democrats and Republicans agree on the need to spruce up the nation's surface transportation system, but disagree on how to fund the work.

Manufacturing technology

The president wants to "fully realize" his plan to build 45 manufacturing innovation centers. These are hubs that take advantage of universities and businesses located close to one another to share technology and ideas before products reach the commercial phase.

Obama has announced four such centers so far.

Oil and gas royalties

Through the Interior Department, Obama proposed changes to the oversight of oil and gas development on federal lands and waters, including royalty reforms and improved revenue collection, to save an estimated $2.5 billion over a decade.

Education

Obama renewed his call for universal pre-kindergarten and expanding the Head Start program, which provides early childhood education for low-income families.

The new budget seeks a total of $68.6 billion through a raise in federal tobacco taxes to vastly expand access to preschool, make all levels of education more accessible and affordable and to connect nearly all students to broadband and high-speed wireless Internet.

Health services

The president sought $77.1 billion for the department that runs Obamacare, Medicare and Medicaid, the Centers for Disease Control and Prevention and biomedical research.

The proposal for the Department of Health and Human Services includes some items aimed at Democratic voters: training to help schools detect mental illness early, extra access to HIV treatment and prevention services and funds to train primary care doctors.