WASHINGTON (CBSDC/AP) — At a time when Mitt Romney is beating President Barack Obama in campaign fundraising, democratic candidates in several pivotal Senate races are raising more money than their GOP counterparts. However, they’ll need the cushion to counter spending by independent conservative groups determined to win a Republican majority.

Democrats outraised Republicans in seven of 10 key races in the April-June period, according to quarterly reports that had to be filed by midnight Sunday with the Federal Election Commission.

In Hawaii, New Mexico and North Dakota, GOP candidates had a fundraising edge.

Democrats say an edge is important because outside groups are investing heavily in an effort to win a Republican majority.

For example, American Crossroads and its affiliate, Crossroads GPS, plans on spending up to $70 million supporting Republican Senate candidates in the fall.

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