sentences:  Due to Texas's unique history, United States sovereignty over Texas has been disputed at times.Adherents of secessionist movements claim that American sovereignty is illegal, although this viewpoint is not widely held.Disputes over the legal status of Texas have revolved around key issues that include, but are not limited to, the legitimacy of its re-admittance to the Union following the Civil War, differing viewpoints over its "de facto" and "de jure" international standing, and perceived discrepancies between its original and current boundaries.