WASHINGTON (Reuters) - Republican proposals to fund an increase in infrastructure spending with user fees would violate President Joe Biden’s pledge not to raise taxes on Americans making less than $400,000 a year, the White House said on Friday. “User fees that have been proposed out there would violate” what is a “red line” for Biden in infrastructure negotiations, White House press secretary Jen Psaki told reporters. Reporting by Trevor Hunnicutt; Writing by Tim Ahmann; Editing by Chris Reese Our Standards: The Thomson Reuters Trust Principles.