She was the vice-chairwoman of the VVD party in the House of Representatives from 2003–2006. In 2006, the chair of the VVD party in the House of Representatives, Jozias van Aartsen, stepped down because of the poor VVD election results in the 2006 Dutch municipal election. De Vries followed van Aartsen's example because she felt "connected" to him. Fellow VVD Parliament member Edith Schippers succeeded her as vice-chairwoman.
When the second Balkenende Cabinet fell and new general elections were announced, de Vries declared she wouldn't return to Parliament after the elections and left Parliament. Shortly before the elections, she published a book about her experiences as vice-chairwoman.