Final answer:
Texas sued the Obama administration chiefly over immigration policy and healthcare, reflecting broader debates over federal and state powers.
Step-by-step explanation:
Between 2009 and 2016, Texas frequently sued the Federal government over a range of issues, most notably immigration policy, health care, and federal-versus-state governmental powers. One of the most contentious issues was the Obama administration's 2014 executive order on immigration, which led to the U.S. v. Texas case where 26 states, including Texas, sought to block the deferral of deportation for certain undocumented immigrants. Additionally, the implementation of the Affordable Care Act, commonly known as 'Obamacare', sparked legal challenges from several states on the role of the federal government in providing healthcare services.