How to eliminate extra margins around text?

Question

I have a problem that the regular text of the article adds extra margins to the specified margins. To make it more clear, whatever I do, the text is "narrower" than what I specify with the geometry package. The main problem is that the algorithm environment and footnotes respect the specified margins, so they look wider than the text. It is somewhat intriguing that when I change the document class from article to report, the problem goes away. However, I need to use article. Any ideas? Here is an example (I added showframe so that it is clear what is happening):

\documentclass[11pt]{article}  
\usepackage{amsmath,amsfonts,graphicx,amssymb}
\usepackage{algorithm}
\usepackage[noend]{algpseudocode}
\usepackage{url}
\usepackage{cite}
\usepackage{enumitem}
\usepackage[colorinlistoftodos]{todonotes}
\usepackage{dsfont}
\usepackage{geometry}
\usepackage{blindtext}
\usepackage{showframe}

\geometry{
  width=6.8in,
  height = 9.2in,
  left=0.9in,
  top=0.9in
}
\let\proof\relax
\let\endproof\relax
\usepackage{amsthm}

\makeatletter
\def\thm@space@setup{\thm@preskip=0pt
\thm@postskip=3pt}
\makeatother

\newtheorem{theorem}{Theorem}[section]
\newtheorem{lemma}[theorem]{Lemma}
\newtheorem{proposition}[theorem]{Proposition}
\newtheorem{claim}[theorem]{Claim}
\newtheorem{fact}[theorem]{Fact}
\newtheorem{corollary}[theorem]{Corollary}
\newtheorem{definition}[theorem]{Definition}
\newtheorem{observation}[theorem]{Observation}
\newenvironment{proof-sketch}{{\bf Proof Sketch:}}{\hfill\rule{2mm}{2mm}}
\newenvironment{note}{\noindent\textbf{Note:}}

\makeatletter
\newenvironment{proofof}[1]{\par
 \pushQED{\qed}%
 \normalfont \topsep3\p@\relax
 \trivlist
  \item[\hskip\labelsep
    \bfseries
Proof of #1\@addpunct{.}]\ignorespaces
}{%
  \popQED\endtrivlist\@endpefalse
}
\makeatother

\title{Title}
\author{
Author
} 
\date{}

\begin{document}
\maketitle
\abstract{}

\thispagestyle{empty}
\newpage

\section{Introduction}
\setcounter{page}{1}
\pagestyle{plain}
\blindtext\footnote{\blindtext}
\end{document}