With polls showing Mitt Romney losing ground to President Obama and some conservatives publicly fretting that he has lost the summer, the presumptive Republican nominee is heading into a critical stretch under pressure to alter the course of his campaign.

Romney will have several chances to do so over the next three weeks, starting with the selection of a running mate, which could come any day. At the end of the month, Republicans will gather in Tampa for a four-day convention that will provide the former Massachusetts governor a chance to reintroduce himself to the country and reset the race on his terms.