Washington ? Republicans are outraising Democrats in nearly a dozen open Senate races, increasing their hopes of significantly narrowing the Democrats’ majority in November.

The differences are dramatic in some cases, such as Ohio. Republican nominee Rob Portman raised $2.6 million in the quarter than ended June 30, compared to about $1 million raised by Democrat Lee Fisher. Portman held a big cash-on-hand advantage: $8.8 million to $1 million, according to campaign finance reports filed Thursday. The two are seeking the seat being vacated by Republican George Voinovich.

Fundraising is more competitive in Kentucky, where GOP Sen. Jim Bunning is retiring. Rand Paul, who won a tough GOP primary, raised $1.1 million for the quarter. Democrat Jack Conway raised slightly less than that from donors, and he lent his campaign another $400,000. Neither campaign had more than $750,000 in the bank at the quarter’s end.

Money separates the viable candidates from the also-rans, allowing hopefuls to run day-to-day campaign operations and buy expensive television ads. Cash also attracts more money from donors. Republicans need a net win of 10 seats to seize control of the Senate, and they’re counting on well-funded candidates to deliver.

Most worrisome to Democrats is their lackluster fundraising in states where their members are retiring. But they are doing better in competitive races where they seek re-election.