Since King Salman bin Abdulaziz Al Saud, 81, came to power in 2015, Saudi Arabia has pursued a foreign policy described by many analysts and diplomats as aggressive - a politically risky departure from its usually discreet diplomacy.
Dr Toby Matthiesen, a senior fellow at Oxford University, told ISS Today that Saudi Arabia thought that 'in order to contain the Arab uprisings and prevent them from reaching the kingdom, it had to pursue a proactive foreign policy and defend its perceived interests forcefully'.
Saudi Arabia's interests include counterbalancing the military and political influence of Iran in the Middle East and beyond. They also include neutralising the potent threats of jihadist groups such as the Islamic State and al-Qaeda, which could gain a foothold in every corner of the Horn.
Saudi Arabia believes these interests can only be protected by assuming an undisputed leadership position, taking coercive diplomatic initiatives when necessary and even using military force. It has accordingly launched military strikes against the Iran-backed Houthi movement in Yemen where Saudi Arabia and Qatar have been separately vying for influence.
The crisis between Saudi Arabia and Qatar has exacerbated conflicts in the Horn
The Saudis viewed the Houthi actions as 'an Iranian ploy to destabilise Yemen and to control it through proxies', researcher in Middle Eastern affairs at the University of Birmingham Umer Karim told ISS Today. He said 'since their military intervention in Yemen, the Saudis have realised that security in Yemen is linked to that of the Horn' - a land of shifting allegiances where suspicion ran maddeningly deep.
And then in early June, Saudi Arabia took the unprecedented initiative of forging an alliance with the United Arab Emirates and Egypt. The makeshift alliance severed diplomatic relations with Qatar and imposed a blockade on it. Saudi Arabia accused Qatar of supporting terrorist groups and entertaining close ties to Iran, which Qatar plays off against Saudi Arabia.
However, the strategic objective of Saudi Arabia's initiative was to stop Qatar punching above its weight and make it comply with the Saudi priority of counteracting Iran.
It is only a slight exaggeration to say that Saudi Arabia's aggressive foreign policy and the resultant diplomatic crisis with Qatar have upset the balance of power among the countries of the Horn. The diplomatic crisis has reignited the border dispute between Djibouti and Eritrea that's been simmering since 2008. Qatar had been mediating the dispute since 2010 and had stationed its troops in the area contested by both countries.
In mid-June, Qatar withdrew its troops after both Djibouti and Eritrea expressed support for Saudi Arabia. Since then, Djibouti - Ethiopia's most important ally - has accused Eritrea of occupying the contested area.
The irony of this is that both Djibouti and Eritrea belong to the same alliance led by Saudi Arabia which, according to Umer, 'wants to root out Qatar's outreach in the Horn region in the same manner they have rooted out the Iranian influence'. On one side, Djibouti has allowed the establishment of a military base by Saudi Arabia on its territory. On the other side, Eritrea has allowed the United Arab Emirates and Saudi Arabia to use the Assab port - adjacent to Ethiopia - for military operations in Yemen.
In June, Saudi Arabia took the unprecedented initiative of forging an alliance with UAE and Egypt
Umer said 'the Saudis and Emiratis needed the logistical support of Horn countries to target the Houthis effectively. In addition to this, they wanted to deny smugglers and Iranian agents the opportunity of supplying arms to the Houthis from ports of the Horn'.
Regarded by many analysts and diplomats as the Horn's foremost power, Ethiopia is concerned by Eritrea's alliance with Saudi Arabia. Cash-strapped Eritrea is trying to undo the regional isolation masterminded by Ethiopia. The two countries have been locked in a bitter political and military conflict since 1998.
In the same vein, Ethiopia and its arch nemesis Egypt - financially dependent on Saudi Arabia and the United Arab Emirates - are at loggerheads over the Grand Ethiopian Renaissance Dam (GERD). The GERD is supported by Sudan at the expense of its historical ally Egypt which accuses Sudan of supporting the ousted Muslim Brotherhood. Egypt was displeased by the visit by a Saudi delegation to the GERD in December 2016, perceiving it - in foreign policy terms - as endorsing Ethiopia's position.
Paradoxically, both Eritrea and Ethiopia cultivate strong ties with Sudan. Sudan has remained neutral in the latest Saudi-Qatari diplomatic crisis. It provided troops to the Saudi-led military campaign in Yemen. Sudan grew so close to Saudi Arabia that it requested it to mediate over the Halayeb border dispute with Egypt.
At the same time, Sudan entertains very close relations with Qatar, which helped it financially and brokered an agreement in Darfur. Qatar has a tense relationship with Egypt for its support to the Muslim Brotherhood and the Arab Spring uprisings.
Saudi Arabia's aggressive foreign policy is a risky departure from its usually discreet diplomacy
Ethiopia is also uncomfortable that Egypt - growing closer to Eritrea - is in the Saudi-led alliance against Qatar, which used to be Eritrea's strongest protector and benefactor. Taking the longer view, Ethiopia improved its relationship with Qatar. Moreover, Qatar is intimately allied to Turkey which has established military bases in Qatar and also in Somalia.
If that wasn't complicated enough, Ethiopia watched its other close ally Somaliland allow the United Arab Emirates to establish a military base in its territory. This base infuriated Somalia which has delicate relations with Saudi Arabia, Qatar, the United Arab Emirates and Turkey.
It is imperative that the Horn countries stay out of the zero-sum diplomatic crisis and keep lines open to both the unrelenting Saudi Arabia and unyielding Qatar. They must also carefully weigh the complexities of the crisis and regionally coordinate their diplomatic involvement.
Berouk Mesfin, Consultant, ISS