According to president Obama and key members of the Government, they don't need the authorization of the US Congress to launch an attack on Iraq. Although the statement wasn't public, it was revealed yesterday after a meeting with Republican Senator Mitch McConnell and other Congress members.
Although the original interventions in Iraq and Afghanistan which began during George W. Bush's presidency were voted and approved in the House of Representatives and the US Senate, the Obama administration considers that – given the fact that the Iraqi government asked officially for help – the intervention could be done according to International law standards.
Obama's declarations coincide with ongoing attacks by the Republicans regarding the lack of transparency on Sargent Bowe Bergdahl's liberation. The announcement of the government's negotiations with the Taliban to free the soldier were never debated or consulted in the US Congress. Neither was the government's intervention in Syria plans last year, which were finally aborted.
As ISIS militia advance closer to Baghdad, various US law makers are pressuring the government for the removal of Al-Maliki's government. The Obama administration allegedly hasn't decided which course of action it will take.
President Obama will deliver a statement on this matter today at 12:30PM Eastern time.