When Lebanese Armed Forces commander Gen. Joseph Aoun asked what his troops should do if Israel violated Lebanese waters, Prime Minister Saad Hariri promptly responded, “You shoot at them.” The maritime dispute with Israel is dominating Lebanese politics as the US State Department’s David Satterfield continues his three-week shuttle diplomacy between the two countries to reach a common ground, or at least prevent the dispute from spiraling out of control.

Hariri’s forceful statement should be viewed through a Lebanese lens and seen as a rejoinder to last week’s speech by Hezbollah Secretary-General Hassan Nasrallah, who offered his armed group as a guarantee that Israel will not intrude in Lebanese waters in the southern border area. Lebanon worries that Israel could use its operations in the Karish gas field to perform directional drilling that would beat Lebanon to the exploration of the adjacent and contested Block 9. Lebanon’s exclusive economic zone map, published in March 2013, includes a small triangular area contested by the two countries, and Beirut prioritized Block 9, which juts into the contested zone, in the first round of offshore licensing. After Israeli Defense Minister Avigdor Liberman on Jan. 31 called Lebanese exploration of Block 9 as “provocative,” the two sides began to trade threats.

This heightened level of tension prompted Lebanon to be on Washington’s radar once again with the visit of the first US secretary of state to Beirut since John Kerry in June 2014. It also signaled the resumption of the 2012-16 mediation by the State Department that was led by Frederic Hof and later Amos Hochstein. Secretary of State Rex Tillerson’s visit to Beirut on Feb. 15 seems to be rather motivated by three priorities: securing a smooth flow of Mediterranean gas; protecting US companies in Israel and Cyprus from any potential conflict; and preventing a scenario where Hezbollah takes charge of the maritime dispute with Israel. Tillerson spent five hours in Beirut traveling from one headquarters to the other to meet the “troika” of President Michel Aoun, parliament Speaker Nabih Berri and Hariri, who had to meet numerous times to reach a consensus on how to respond to the US mediation. Berri represents the hawkish voice that focuses on deterring Israel, and Hariri the pragmatic one who said during the press briefing with Tillerson that the Lebanese government is open to a solution “that will be fair to us and fair to everyone.”

However, it is becoming clear that the US mediation has reached an impasse once again. Lebanon’s idea to have the United Nations Interim Force in Lebanon take the lead on demarcating the maritime border requires a UN Security Council decision to expand the mandate of the UN peacekeeping forces. Israel wants to build a wall according to the Blue Line, or the UN-mediated line of the Israeli withdrawal in 2000, while Beirut wants the land border to be according to the 1923 demarcation line between Lebanon and Palestine. These technical discussions mean that the dispute between the two countries is over 860 square kilometers (330 square miles) of water and 13 points on the land border. The United States agrees with Lebanon that a border deal should be reached before Israel builds a security wall.