How to set equal right margin by geometry package?

Question

It is weird that with the following options, geometry doesn't set the equal right margin, it will be alternating on even and odd pages:

\newgeometry{hmargin={.5in,1.5in},vmargin={0in,0in}}

I want to have all the page have right margin 1.5in and left margin 0.5in, how to do this? MME:

\documentclass{amsart}
\usepackage{geometry}
\usepackage{lipsum}
\begin{document}
\newgeometry{hmargin={.5in,1.5in},vmargin={0in,0in}}
\lipsum
\lipsum
\newpage
\lipsum
\end{document}

Answer 1

This is because the amsart issues the following

\ExecuteOptions{leqno,centertags,letterpaper,portrait,%
  10pt,twoside,onecolumn,final}

which sets the default options of the class. Note that this includes twoside, which necessarily implies a different left (typically even) and right (typically odd) page layout. geometry follows this requirement, switching the left/right margins according to the page number (odd or even).

If you want to maintain a consistent layout from one page to the next, issue oneside as part of the document class options:

\documentclass[oneside]{amsart}