Last weekend, the government of Bahrain announced they had intercepted a shipment of explosives and weapons from Iran. Two Bahraini nationals confessed to being the conduit for the weapons, and the explosives used in yesterday's attack matched those smuggled into the country.

Two policemen in Bahrain were killed and several injured in a terrorist attack that the tiny nation says was engineered by Iran.

BBC:

Bahrain has suffered unrest since a 2011 uprising in which the Shia majority demanded reforms from the Sunni-led government. The latest attack comes just days after Bahraini authorities said they had foiled an arms smuggling plot linked to Iran. Two Bahrainis were arrested after they admitted receiving a shipment of explosives, automatic weapons and ammunition from Iranian handlers, officials said. Bahrain's government has previously accused Iran of supporting Shia militants in the kingdom. It also recalled its ambassador to Tehran on Saturday, over "hostile comments" by Iranian leaders. The explosion in Sitrah is the latest in a series of blasts that have targeted police in villages with a predominately Shia population. Roads leading into the town were blocked by officers, as the wounded were taken to hospital. Iran has always denied interfering in Bahrain, although it acknowledges it does support opposition groups seeking greater political and economic rights for the Shia Muslim community.

Bahrain has long been on Iran's target list, largely because of its Shia majority, but also because of its strategic position in the Persan Gulf. It's made up of 30 islands off the coast of Saudi Arabia in the Gulf and has immense oil wealth.

The nation of a little more than a million people (only half being native Bahrainis) is ruled with an iron fist by the absolute monarchy of King Hamad. Most of the wealth is concentrated in the hands of the monarchy and its Sunni allies. This has bred a low-level rebellion by the majority Shias that's being financed and supplied by Iran.

The significance of the nuclear deal to Bahrain and Saudi Arabia is immediately apparent. Bahrain is a dagger aimed at the heart of Saudi Arabia, and if the Iranians get control, it would make life extraordinarily uncomfortable for the kingdom. The sanctions relief being granted Iran will allow them to turn up the pressure on King Hamad's rule, perhaps reigniting the large-scale protests seen in 2011, when Hamad was forced to turn to Saudi Arabia and the Gulf Cooperation Council to restore order.

Bahrain is a tiny country balanced on the knife's edge of Iran's geopolitical and regional ambitions and a creaky, oppressive monarchy. When the Congress considers this deal, it might keep Bahrain in mind.