When Monroe was younger, he had aspired to become Minister for Magic. Indeed, so far as anyone knew, he still aspired to that position. It was a common dream, to want to achieve high office, and the status that came with it. And it was convenient, to let people believe one dreamed common dreams.
Monroe had, of course, planned his rise to the top meticulously. Or as meticulously as one could. He had trained in Occlumency, because many people would want access to the Minister's mind for any number of reasons. He had started at the bottom, and tried to see what made the Ministry tick. He had bided his time, waiting until he was "old enough" to be credible. And waiting for an opportunity.
He walked down the corridor toward Robert Lupin's office. Monroe had given up his wish to become Minister years ago, but there was still a particular position he had his eye on, and now was the time to get it.