Historically, relations between Afghanistan and the US can be dated back to 1919, when King Amanullah, the reformist monarch of Afghanistan, dispatched the first Afghan envoy to Washington following independence from Britain.  However, full diplomatic relations were only established in 1934 and 1935, when the two countries designated ambassadors to the respective diplomatic missions. If we politically analysis the bilateral relations between the two nations, we would find that relations between the US and Afghanistan, since the establishment of diplomatic exchanges, have been characterized by inconsistent patterns of tension and collaboration. 
The U.S supported Afghanistan After the fall of the Taliban, to have a broad-based government, representative of all Afghans, and actively encouraged a UN role in the national reconciliation process in Afghanistan. The U.S. has made a long-term commitment to help Afghanistan rebuild itself after years of war.
BSA the road Map of the Afghan and US strategic partnership
Building on the Enduring Strategic Partnership Agreement between the Islamic Republic of Afghanistan and the United States of America, signed 2 May 2012, the two countries signed the Bilateral Security Agreement (BSA) on 30 September 2014. The BSA reaffirms that Afghanistan and the United States are committed to strengthen long-term strategic cooperation in areas of mutual interest, including: advancing peace, security, and stability, strengthening state institutions, supporting Afghanistan’s long-term economic and social development, and encouraging regional cooperation. The strategic goal of the BSA was enabling that Afghanistan can independently secure and defend itself against internal and external threats, and help ensure that terrorists never again encroach on Afghan soil and threaten Afghanistan, the region, and the world.
How the Strategic Partnership Shall Continue After the Peace Deal
The US and Taliban have constantly negotiated on a US Troops withdrawal framework during the six rounds of peace talks in Doha of Qatar. First, Taliban are not the sole decision makers about Afghanistan; it is a fact that Taliban only represent some hardline Pashtuns and not all Pashtuns of Afghanistan. As a result, they even do not represent Pashtuns, and they cannot represent the other ethnic groups of Afghanistan. While Taliban insist on the withdrawal of the US forces, the majority of Afghans supports the military presence of the US in the country and appreciates the great role the US and its allies have played in Afghanistan to develop security infrastructure and support Afghanistan Security and Defense forces. Further, Afghanistan remains an important partner of the United States in the fight against terrorism, working with US to eliminate al-Qaeda, IS-Khorasan (IS-K) and their affiliates in Afghanistan. In order to strengthen Afghanistan’s capabilities as a partner, and to improve the lives of the Afghan people, the US shall continue to invest U.S. resources to help Afghanistan improve its security, governance, institutions and economy. As ISK is just gaining power in Afghanistan and strengthening its stronghold in the country,   the US shall maintain a counterterrorism presence as long as an insurgency continues in Afghanistan if it wants Afghanistan not to change to a safe haven for the terrorist groups to threaten the regional and international community. In addition to ISK, there are more than 20 international terrorist groups in the country with factories producing suicide bombers. As a result, without the US Support, any government in Afghanistan will collapse in 6 months.
Bilateral Economic Relations
If there is a peace deal between the US and Taliban, the US shall commit sustainable economic and development to Afghanistan. In fact, there shall be a Strategic Partnership Agreement signed between the two countries on sustainable economic and development support. Such an agreement shall be the primary forum for bilateral trade and investment discussions between the two countries.
Sustainable U.S. and other international community support to Afghanistan in a variety of areas, including humanitarian relief and assistance, capacity-building, security needs, counter-narcotic programs, and infrastructure projects can ensure a sustainable peace deal in Afghanistan. The only way to ensure that Afghanistan, never-again, becomes a staging-ground for international terrorist attacks against the US and allies is supporting the installation of an elected government based on the current Afghan constitution. No theocracy government will ensure peace in the country and it only will act as the primary cause of the new round of civil war in Afghanistan that can ultimately change it once more to the safe haven of the terrorist groups.