WASHINGTON — Republicans and Democrats are pressing for major legislation to counter rising threats from China, but mere weeks into the new Congress, a bipartisan consensus is at risk of dissipating amid disputes about what steps to take and a desire among many Republicans to wield the issue as a weapon against President Biden.

In the House and Senate, leading lawmakers in both parties have managed in an otherwise bitterly divided Congress to stay unified about the need to confront the dangers posed by China’s militarization, its deepening ties with Russia and its ever-expanding economic footprint.

But a rising chorus of Republican vitriol directed at Mr. Biden after a Chinese spy balloon flew over the United States this month upended that spirit — giving way to G.O.P. accusations that the president was “weak on China” — and suggested that the path ahead for any bipartisan action is exceedingly narrow.

“When the balloon story popped, so to speak, it felt like certain people used that as an opportunity to bash President Biden,” said Representative Raja Krishnamoorthi of Illinois, the top Democrat on the select panel the House created to focus on competition with China.