Donald Trump’s refusal to acknowledge his loss in the 2020 election has fed concerns that the presidential transition would be sabotaged, as a Trump appointee refused to sign off on funding for the transition and the Trump campaign announced an expanded legal strategy in a quest to reverse the election result.

The Center for Presidential Transition, a nonpartisan advisory board, urged the Trump administration on Sunday to begin the handoff to staff supporting Joe Biden, whose victory continued to grow in magnitude as states completed their ballot counts.