 WASHINGTON (Reuters) - A Supreme Court nomination battle that was ignited on Saturday with the death of Justice Antonin Scalia has given Democrats an explosive new issue that could bolster their chances of regaining majority control of the U.S. Senate.  The impact could be felt most acutely in “swing” states, where Republicans are trying to hold onto Senate seats, political strategists and analysts said. The high stakes are also expected to prompt greater voter turnout that could favor Democrats.ALSO ON REUTERS Trump is a ------: White House hopeful plays fill-in-the-blanks with voters Not in my backyard? Mainstream Scandinavia warily eyes record immigration With no clear idea of who President Barack Obama will nominate as Scalia’s replacement, it was way too early to know exactly how this fight will play out in already rollicking presidential and congressional elections.  But, “in this hyper-polarized political environment we are currently operating in, I can only assume the battle over this (court) nominee will dominate the political debate from here on out,” said Jim Manley, a strategist and former top aide to Democratic senators.  Manley noted Republicans are facing tough races for Senate seats in swing states such as Ohio, Florida, New Hampshire, Wisconsin and Pennsylvania and could find themselves in even tighter spots because of the divisive fight over Scalia’s replacement.  These Republican candidates, who either already serve in the Senate or are vying for open seats, have to especially thread the needle in their politically divided states on social issues, like abortion rights, that so dominate Supreme Court confirmation fights.  Democrats already enjoyed an advantage in the November Senate elections, having to defend only 10 seats while 24 Republican seats are up for grabs in the 100-member chamber.  Democrats need a net gain of five seats to win back the majority they lost in the 2014 elections.  Just hours after Scalia’s death at the age of 79, Senate Majority Leader Mitch McConnell proclaimed that whoever moves into the White House on Jan. 20, 2017 - and not Obama - should pick the replacement for the late conservative jurist.  The Senate must confirm presidential nominees to the life-time appointments at the nine-justice high court, whose recent decisions have had a deep impact on the country, from the legalization of same-sex marriage to election campaign finance.  “If the Republican leadership refuses to even hold a hearing, I think that is going to guarantee they lose control of the Senate, because I don’t think the American people will stand for that,” proclaimed Democratic Senator Patrick Leahy, who was interviewed on CNN’s “State of the Union” on Sunday.    Meanwhile, McConnell’s announcement sparked new fundraising pleas in the presidential and congressional campaigns, which already were awash in campaign contributions.  Ron Bonjean, a former top Republican Senate leadership aide and current political strategist, acknowledged that Republican Senate candidates from swing states “may be placed in an awkward position” by the Supreme Court fight.  While some may be pressured to join Democrats in calling for a confirmation vote depending on who Obama nominates, Bonjean also saw a potential upside for those Republicans.  With anti-establishment candidates like Donald Trump and Bernie Sanders far exceeding expectations in their quest for the presidency, Republican Senate candidates in swing states could feel emboldened to break from party ranks.  Senator Mark Kirk in Illinois, for example, is one of those Republicans in a swing state facing a potentially rough race.  The 2016 campaigns already were generating an avalanche of voter interest with control of the White House and Congress hanging in the balance.  Now, with the ideological control of the Supreme Court also to be decided, “That leads to only one conclusion: Increased turnout” of voters in November, said Larry Sabato, a University of Virginia political scientist.  Higher turnout often helps Democratic presidential candidates, which in turn could help Democratic Senate candidates.  However, Sabato also noted that with the Supreme Court vacancy ascending in importance, it could rally establishment Republicans who currently oppose the anti-establishment Trump to support him if he becomes the party’s nominee.  And that, in turn, could boost Republican turnout in tight Senate races.  