She became a member of the House of Representatives on 17 June 2010 on behalf of the Party for Freedom (PVV), focusing on matters of the judiciary.

In September 2023, Helder switched to the Farmer–Citizen Movement (BBB), and she subsequently served as the party's spokesperson for justice, security, and the interior.

Along with Ulysse Ellian (VVD), Helder was rapporteur for the Committee for Justice and Security on the overhaul of the Code of Criminal Procedure [nl], and she called in sick in December 2024, when her party decided that it would not prioritize the issue.

On 3 February 2025, she announced her resignation from the House, citing irreconcilable disagreements with party leader Caroline van der Plas.

In addition to her recent experiences, Helder was disappointed that she had not been included by the BBB in formation talks, and she revealed that she had not endorsed the resulting coalition agreement, discontent with its provisions on justice and security.