But Jimmie Akesson's desire for a vote has scant backing among the public and the other established parties. Even his own Sweden Democrats are lukewarm to the idea, and in any case have no desire to give up access to Europe's internal market.
While polls show outright support for the EU is just above 50 percent, the number of Swedes who actually advocate leaving is below 20 percent. Even the other party that backs a potential "Swexit" says a referendum is very far off.
"There's a public majority in favor of the EU and we respect that," said Ulla Andersson, a key official for the Left Party, which has supported the Social Democratic-led government over the past four years. "If there's eventually a public majority against the EU then we'll decide on it then."
Public opinion has changed quickly and surprisingly in the past, of course. Key examples include the U.K.'s vote to leave the EU and the election of Donald Trump in the U.S. The Sweden Democrats are also emerging as a power broker, and could win more than 20 percent of the vote in September, after barely making it into parliament for the first time in 2010.
That has Finance Minister Magdalena Andersson raising a finger of warning, declining to rule out that a new referendum could eventually happen. It "depends completely on what influence the Sweden Democrats are given over a government formation," she said, emphasizing that the Social Democrats have pledged not give the Sweden Democrats any leverage.
The four parties in the opposition alliance are also staunch EU supporters.
The Sweden Democrats for now pledge that a referendum won't be used as a political cudgel. Speaking after his leader called for a referendum, Oscar Sjostedt, the party's spokesman on economic policy, said that it won't seek to use the issue in any post-election government talks. The party's view is that big issues such as EU membership or joining NATO should be settled by a referendum.
It's also far from the majority needed to bring about a referendum. The nationalists may end up as the second-largest party, but because of their neo-Nazi roots, none of the traditional parties have so far been prepared to form a government with them.
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The nationalists want to stay in the single market, but also to put some limits on the free movement of people.
"We need free movement of services, goods and capital, but for people it's a bit more complex because there's begging and crime," Sjostedt said.
Andersson said the party needs to level with the Swedish people.
"To leave the EU, stop paying and still have access to the single market, that will never happen," she said. "To try and give that impression is not being honest with the Swedish people."
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)
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