Democratic candidates in some of the most critical Senate races in the country are surging, putting the party in its best position of the election cycle to keep its majority in November.

The reasons range from the post-convention bounce led by President Barack Obama, to potent Democratic attack ads, to anemic performances of some GOP candidates.

Fresh polling in marquee contests shows a distinct trend line in the Democrats’ favor, making the GOP’s narrow path to a Senate majority significantly more difficult with less than two months until the election.