"President Assad is not indispensable and we have absolutely nothing invested in him remaining in power…from our perspective, he has lost legitimacy," U.S. Secretary of State Hillary Clinton said Tuesday – suggesting for the first time that Washington may support toppling the Syrian regime.

Although Clinton was responding to attacks on the U.S. and French embassies in Damascus by pro-Assad protesters, her words indicate a sharp deterioration in the relations between the two countries.

Just last January, two days after riots erupted in Tunisia, the U.S. sent an ambassador to Syria for the first time after a six-year diplomatic freeze. Washington assumed it could engage in a political dialogue with Damascus, and considered Syria a future partner in stabilizing the security situation in Iraq and curbing Iran's regional influence.

When the demonstrations broke out in Syria, the U.S. avoided taking a firm stand against Assad, but rather stated that the Syrian regime must introduce reforms, uphold a democracy and stop suppressing the protests. Moreover, the sanctions put forward against Syria were intended to force the existing regime to comply with the protesters' demands, but not to oust Assad or dismantle his political mechanisms.

Washington estimated that Assad will stay in power anyway, and that perhaps that would serve U.S. interests better by blocking Iran's influence from extending into Syria – as it is in Iraq – in addition to her already strong sway over Lebanon.

Therefore, the U.S. saw in the prospect of a national dialogue between the authorities and the opposition a possibility for leverage that would change the regime's policies without toppling it. Syrian opposition members have also claimed that they came under U.S. pressure to engage in dialogue and reconcile with the government.

Indeed, some opposition members who took part in the national dialogue conventions refrained from calling for Bashar's departure and limited their demands to political and economic reforms. By doing so, they infuriated other opposition groups who demand reforms be introduced only after the regime changes.

It seems now that Washington also understands the Syrian national dialogue is nothing but a government attempt to show it is willing to introduce reforms, but without including a detailed plan or a timeline.

Together with the attack against the U.S. embassy in Damascus (which invoked bitter memories of the Iranian Revolution of 1979), Washington will soon need to decide whether it is willing to stand by the protesters through force or settle for diplomatic steps. One of these steps might be recalling the U.S. ambassador from Damascus, but this may present President Obama with a dilemma – the ambassador was appointed without Congress's approval, knowing very well it would not have supported the move. Therefore, this appointment is limited to a one year period. Obama knows if he recalls the ambassador it will be extremely difficult to appoint a new one – unless the Syrian regime changes.