By Patricia Zengerle WASHINGTON (Reuters) – Democratic and Republican U.S. Senate leaders introduced a resolution on Monday backing Sweden and Finland’s bids to join NATO, underscoring support for expanding the alliance despite growing nationalism in the Republican party. It will take a two-thirds majority in the 100-member Senate to approve the expansion of the alliance, requiring “yes” votes from at least 17 Republicans along with every Democrat. Many U.S. Republicans have been following the lead of former President Donald Trump – the party’s leader – toward more nationalist foreign policy. …