Chinese bombers. Chinese hypersonic missiles. Chinese cyberattacks. Chinese anti-satellite weapons.

To a remarkable degree, the 2020 Pentagon budget proposal is shaped by national security threats that acting Defense Secretary Patrick Shanahan has summarized in three words: "China, China, China."

The U.S. is still fighting small wars against Islamic extremists, and Russia remains a serious concern, but Shanahan seeks to shift the military's main focus to what he considers the more pressing security problem of a rapidly growing Chinese military.

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This theme, which Shanahan outlined Thursday in presenting the administration's proposed 2020 defense budget to the Senate Armed Services Committee, is competing for attention with narrower, more immediate problems such as President Donald Trump's effort to use the military to build a border wall. The hearing, for example, spent more time on the wall and prospects for using military funds to build parts of it than on any aspect of foreign policy, including the conflict in Syria or military competition with China, Russia or North Korea.

The proposed budget would give the administration enough funds to complete 722 miles of wall, at a projected cost of $25 million per mile. The White House is also requesting $3.6 billion to pay back the money the administration plans to redirect under the president's national emergency declaration.

Shanahan is hardly the first defense chief to worry about China. Several predecessors pursued what the Obama administration called a "pivot" to the Pacific, with China in mind. But Shanahan sees it as an increasingly urgent problem that exceeds traditional measures of military strength and transcends partisan priorities.

"We've been ignoring the problem for too long," Shanahan told a senator.

"China is aggressively modernizing its military, systematically stealing science and technology, and seeking military advantage through a strategy of military-civil fusion," he wrote in prepared testimony to the committee, which is considering a $718 billion Pentagon budget designed in part to counter China's momentum.

In this March 14, 2019, photo, acting Defense Secretary Patrick Shanahan goes before the Senate Armed Services Committee to discuss the Department of Defense budget, on Capitol Hill in Washington. J. Scott Applewhite/AP

The $25 billion the Pentagon is proposing to spend on nuclear weapons in 2020, for example, is meant in part to stay ahead of China's nuclear arsenal, which is much smaller than America's but growing. Shanahan said China is developing a nuclear-capable long-range bomber that, if successful, would enable China to join the United States and Russia as the only nations with air-, sea- and land-based nuclear weapons.

Shanahan ticked off a list of other Chinese advancements — hypersonic missiles against which the U.S. has limited defenses; space launches and other space efforts that could enable it to fight wars in space; "systematically stealing" of U.S. and allied technology, and militarizing land features in the South China Sea.

Bonnie S. Glaser, director of the China Power Project at the Center for Strategic and International Studies, said the U.S. has been lacking effective strategies for competing with China on a broad scale.

"It is overdue," she said of the Shanahan focus. "We have been somewhat slow in catching up" in such areas as denying China its regional ambitions, including efforts to fully control the South China Sea, which is contested by several other countries.

Some defense analysts think Shanahan and the Pentagon have inflated the China threat.

"I do think it's worth asking what exactly is threatening about China's behavior," said Christopher Preble, vice president for defense and foreign policy studies at the Cato Institute. He doesn't discount China as a security issue, including in the South China Sea, but doubts the U.S. military is the institution best suited to deal with such non-military problems as cyber intrusions into American commercial networks.

In Preble's view, competition with the Chinese is not mainly military. "I still don't believe the nature of the threat is quite as grave as we're led to believe" by the Pentagon, he said. "They tend to exaggerate the nature of the threat today."

In his previous role as deputy defense secretary, Shanahan and President Trump's first defense secretary, Jim Mattis, crafted a national defense strategy that put China at the top of the list of problems.

"As China continues its economic and military ascendance, asserting power through an all-of-nation long-term strategy, it will continue to pursue a military modernization program that seeks Indo-Pacific regional hegemony in the near-term and displacement of the United States to achieve global pre-eminence in the future," that strategy document says.

That explains in part why the U.S. is spending billions more on space, including means of defending satellites against potential Chinese attack, and on building hypersonic missiles to stay ahead of Chinese and Russian hypersonic weapons development.

It also explains some of the thinking behind preparing for an early retirement of the USS Harry Truman aircraft carrier, a strategy that views carriers as a less relevant asset in a future armed conflict involving China.

This concern about countering China has permeated the entire U.S. military. Gen. Thomas Waldhauser, head of U.S. Africa Command, said last month that dozens of African heads of state were invited to Beijing last fall to consider billions in Chinese loans and grants, and that China is building thousands of miles of railroads in Africa, mostly linked to Chinese mineral extraction operations.

"They're heavily invested and heavily involved" in Africa, he said.

The top U.S. commander in Europe told Congress this week that China also is making inroads in Europe.

"China is looking to secure access to strategic geographic locations and economic sectors through financial stakes in ports, airlines, hotels, and utility providers, while providing a source of capital for struggling European economies," Gen. Curtis Scaparrotti said.

Mr. Trump's 2019 proposal includes $750 billion in military spending, and 5 percent cuts in non-defense domestic discretionary spending across the board. Total spending cuts would total $2.7 trillion over 10 years, the administration official said, with the goal of balancing the budget by 2034.