Mitt Romney rolled to a double-digit victory in Washington state's Republican presidential caucuses Saturday night, his fourth campaign triumph in a row and a fresh show of strength in the run-up to 10 Super Tuesday contests in all regions of the country.

Rick Santorum and Ron Paul battled for second place, while Newt Gingrich ran a distant fourth.

Romney's victory came on the heels of twin primary triumphs over Santorum earlier in the week in hard-fought Michigan and lightly contested Arizona, as well as a narrow win over Paul in Maine caucuses earlier in February.

Returns from caucuses in 43 percent of Washington state's precincts showed Romney with 37 percent of the vote, while Paul and Santorum each had 24 percent. Gingrich was drawing 11 percent.

There were 40 delegates at stake, and a likelihood that at least two of the contenders for the nomination to oppose President Barack Obama would add to their totals.

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