Cancelling \ragged commands

LaTeX provides commands \raggedright and \raggedleft, but none to cancel their effect.

The following code (to be inserted in a package of your own, or as internal LaTeX code) defines a command that restores flush justification at both margins: 

\def\flushboth{%
  \let\\\@normalcr
  \@rightskip\z@skip \rightskip\@rightskip
  \leftskip\z@skip
  \parindent 1.5em\relax}
There's a problem with the setting of \parindent in the code: it's necessary because both the \ragged commands set \parindent to zero, but the setting isn't a constant of nature: documents using a standard LaTeX class with twocolumn option will have 1.0em by default, and there's no knowing what you (or some other class) will have done.