Four days after a mass shooting in San Bernardino, California, US President Barack Obama defined the attack as "an act of terrorism" in a rare Oval Office address on Sunday. Obama illustrated his understanding about the evolution of terrorism, the international coalition on anti-terrorism, gun control and Islamophobia. He reaffirmed a pathway to achieve a "sustainable victory" by reiterating policies and countermeasures.

The last time Obama delivered such a prime-time speech was in 2010, when he cheered the end of US combat operations in Iraq.

However, five years later, the Islamic State (IS), the new specter conjured from the war chaos, keeps haunting the US and its allies more violently. As Obama said in the speech, the threat of terrorism to the US has "entered a new phase." The US might be able to prevent its homeland from "complex multifaceted attacks like 9/11," but threats from "less complicated acts of violence like the mass shootings" are posing more risks to US society.

Ideological penetration by the IS is breaking down the defense from the inside. Mass shootings and bombings plotted by domestic terrorists have proven their capability of causing larger harm and panic. This is a consequence that the US probably did not anticipate when it made waves in the Middle East.

Struggling to calm public fears while avoiding offense to the Muslim population, Obama did not forget to guarantee his people that the US is still the leader in an international coalition against terrorism. But Obama's pledge to defeat the IS sounds less convincing to people of other countries that are also under threat of rampant terrorism.

In his speech, Obama urged Congress to vote to authorize the continued use of military force against these terrorists. But how the US will use its military power in the turbulent region, to fight terrorism or to realize its political gains, is of wide concern.

The US has never been truly committed to anti-terrorism. Washington doesn't care about breaking its promises and regards terrorists as tools for practical and geopolitical interests. That is why Washington made the downfall of Bashar al-Assad as a precondition to be more engaged in the fight against the IS in Syria. A country cannot be the leader of an endeavor if it has no strategic commitment to the public good.

Obama tried to offer many assurances to his compatriots, without many detailed strategies. Anti-terrorism will prevail in the form of a coalition, but Washington should be a real participant instead of a half-hearted player.