Lincoln-Douglas Debate involves two solo students debating as individuals. Topics generally focus on a resolution that calls for an evaluation of a moral statement or a call to action. The call for action may be by an individual, nation, or other entity. Sides are pre-determined by the tabulation room except in the occasional case of specifically designated 'flip for side' debates.
Lincoln-Douglas is value debate. Values are often seen as principles or concepts that people believe in. Often (but not always) Lincoln-Douglas topics will focus on value implications of policy topics. In other words, before deciding what type of public schools or taxation system we should have, it is necessary to decide if public education or taxation are something we should have in the first place, given the values of the given community.
Students are not responsible for particular practical/policy applications. However, if particular practical/policy applications are intrinsic to advocated value systems, particular applications may or may not be an appropriate issue to be debated in a given round. Reasons to consider or not to consider any given argument should be clearly articulated in the round. Lincoln-Douglas is not necessarily a single value debate, though most students will choose to debate using such a framework. Other methods are permissible. Many, but not all students will offer voting standard/criteria/criterion as a means to adjudicate the round. In so far as possible, the judge should evaluate the importance of argued issues applied to the most convincing standard advocated by the students.