Sen. Max Baucus responds to a question during his confirmation hearing to be the U.S. ambassador to China before the Senate Foreign Relations Committee on Jan. 28. (Shawn Thew/EPA)

The Obama administration’s choice to be the next U.S. ambassador to China on Tuesday signaled a tougher public stance on simmering commercial and security disputes, pledging to tell Beijing, “Uh-uh, we won’t be taken advantage of.”

Sen. Max Baucus (D-Mont.) said he will make it clear that the United States wants trade, engagement and cooperation with China but will stand firm on principles of human rights, intellectual property, free trade and freedom of navigation in the South China and East China seas.

“It’s the old thing in life; be fair but firm,” Baucus told the Senate Foreign Relations Committee, describing his posture toward China’s growing list of territorial disputes with neighboring nations and challenges to the United States at sea.

The six-term Democrat, who has announced plans not to seek reelection, is expected to gain quick confirmation to a post that is among the most high-profile and difficult diplomatic assignments.

A longtime chairman of the Senate Finance Committee, Baucus has little direct experience with the security and military portfolios that are an increasingly large part of the U.S. relationship with China. “I’m no real expert on China,” Baucus said at one point.

He later agreed with Sen. John McCain (R-Ariz.) that China is acting largely out of a nationalist view that it should be the primary power in Asia.

When advancing U.S. maritime and military interests, including the obligation to defend Japan, Baucus said he would apply his trademark straight-talking approach.

That means saying directly that the United States opposes new air defense zones and other Chinese moves to expand its security presence in Asia, Baucus said, and working to avoid “a major dispute, a major problem” if confrontation goes too far.

Baucus said he believes that China views security issues through a clear prism: “China takes care of its part of the world,” as he put it, “and the rest of the countries take care of their parts of the world.”

Baucus, 72, would replace Gary Locke, a Chinese American former governor and commerce secretary who had a strained relationship with the Chinese leadership and announced plans to leave his post earlier than expected.

Baucus said he would encourage China to play by international rules as it gains global clout.

“I have become a firm believer that a strong geopolitical relationship can be born out of a strong economic relationship, which often begins with trade,” Baucus said.

Baucus pledged to strongly defend U.S. views on human rights and religious liberty, calling them the foundation of American democratic ideals. But he would not promise Sen. Marco Rubio (R-Fla.) that he would visit a “house church” in China, one of the homes or private places where Catholic and Protestant groups worship, often in secret. The Chinese government has long persecuted members of such churches.