Law firms in Washington are gearing up for what attorneys say could be a crucial debate over U.S. tax policy — one that might usher in the most extensive tax code changes in the past 20 years.

Firms are trying recruit top tax attorneys, especially from Capitol Hill and the Bush administration, building lobbying coalitions and educating clients about what’s at stake. Kirkpatrick & Lockhart Preston Gates Ellis won the latest hot hire, beating out five rivals this month to nab former Senate Finance Committee tax counsel Patrick Heck.