The turmoil that’s threatening to topple Prime Minister Justin Trudeau has members of his political party poring over the rulebook for replacing him.

Calls are growing from within the Liberal caucus for Prime Minister Justin Trudeau to step down as party leader — and some have pegged Chrystia Freeland as their choice to replace him.Twenty-one Liberal MPs have publicly urged Trudeau to resign — many of them within the last week — after Freeland shocked Canadians on Monday by resigning as deputy prime minister and finance minister hours before she was supposed to table the government's fall economic statement.

The pressure comes after a turbulent week for Trudeau, including the resignation of  Deputy Prime Minister and Finance Minister Chrystia Freeland over spending disagreements and a declaration by opposition parties to unite and bring down his minority government.