It shall be unlawful for a labor organization or its agents to picket or cause to be picketed, or threaten to picket or cause to be picketed, any employer where the primary object thereof is forcing or requiring an employer to recognize or bargain with a labor organization as the representative of his employees, or forcing or requiring the employees of an employer to accept or select such labor organization as their collective bargaining representative

    (1) Where another labor organization has been certified or has been lawfully recognized in accordance with this act and a question concerning representation may not appropriately be raised under section 27, or

    (2) Where, within the preceding twelve months a valid election under section 27 has been conducted,

     unless the picketing labor organization is currently certified or lawfully recognized as the representative of such employees.