Rails Way for dynamic link_to
Your link_to is set to POST but you are adding the statement_type on the url like if it were a GET request? Sounds like you are mixing things and you can resolve this using just a single form element without JS if I understand you right.

&lt;%= form_tag new_statement_template_path, method: :post %&gt;
  &lt;div class="form-group"&gt;
    &lt;%= select_tag :statement_type, options_for_select(Statement.statement_types.keys.to_a) %&gt;
  &lt;/div&gt;
  &lt;div class="modal-footer"&gt;
    &lt;button type="button" class="btn btn-default" data-dismiss="modal"&gt;Cancel&lt;/button&gt;
    &lt;%= submit_tag "New Form" %&gt;
  &lt;/div&gt;
&lt;% end %&gt;


Now your controller action will have a the selected option at params[:statement_type].