WASHINGTON (Reuters) - Katherine Tai, President Joe Biden’s nominee for U.S. Trade Representative, vowed to U.S. senators that she would work to strengthen U.S. supply chains, enforce a new trade deal with Canada and Mexico, and hold China to its trade promises. In written testimony prepared for her confirmation hearing before the Senate Finance Committee on Thursday, Tai underscored the Biden administration’s determination to pursue new longer-term trade policies to focus on “workers and wage earners,” support U.S. innovation and enhance U.S. competitiveness abroad. As the trade “czar” for the world’s largest economy, biggest importer of goods and second-largest exporter after China, Tai would wield immense clout, especially after four years of trade turmoil sown by former President Donald Trump. If confirmed, as expected, Tai faces a long list of challenges, including a push by allies who want Washington to rescind tariffs imposed by Trump on steel and aluminum, aircraft and wine. Tai, the top trade lawyer for the House of Representatives Ways and Means Committee and a fluent Mandarin speaker, said it was critically important that the United States have a strategic and coherent plan to deal with China and help U.S. companies compete with its model of “state-directed economics.”In her testimony, Tai said she would prioritize rebuilding U.S. alliances and re-engaging with international institutions, to better address common threats like climate change, the COVID-19 pandemic and a global economic downturn, while investing to make the U.S. economy more resilient. “China is simultaneously a rival, a trade partner, and an outsized player whose cooperation we’ll also need to address certain global challenges,” she said in the prepared testimony, which was seen by Reuters. “We must remember how to walk, chew gum and play chess at the same time,” she said. Tai’s testimony has been anxiously awaited for months by industry, U.S. trading partners from Beijing to Brussels, labor groups and lawmakers - all in a long queue to lobby Tai as soon as she is confirmed. Tai said she would make it a priority to implement and enforce the U.S.-Mexico-Canada trade agreement that she helped renegotiate in 2019 to include tougher labor and environmental standards. She said the deal marked an “important step in reforming our approach to trade” and its success was vital.