TOKYO (Reuters) - Pledges to spend on education and child care, stay tough on North Korea and revise the pacifist constitution are likely to be pillars of Japanese Prime Minister Shinzo Abe s campaign in a snap election next month, government sources said on Tuesday. Abe is expected to announce on Monday that he will call a general election on Oct. 22 to take advantage of a rebound in his damaged approval ratings and disarray in the opposition, ruling party and government sources said. The prime minister, whose ratings have recovered from below 30 percent in July, is betting his ruling bloc can at a minimum retain a simple majority in the chamber and at best keep the two-thirds super-majority needed to achieve his long-held goal of revising the constitution to clarify the military s role. A solid victory would boost Abe s chances of a third term as ruling Liberal Democratic Party (LDP) leader in a party election next September, putting him on track to become Japan s longest-serving premier.  That is his biggest goal,  said veteran independent political analyst Minoru Morita.  Abe s support rose 6.5 points to 50.3 percent in a poll conducted over the weekend by the Sankei newspaper and the Fuji News Network, while backing for the LDP was at 38 percent compared to 6.4 percent for the main opposition Democratic Party. Abe wants to go ahead with a planned rise in the nation s sales tax to 10 percent from 8 percent and use some of the revenue to create a  social security system for all generations , which would invest in education while decreasing the proportion of sales tax revenue used to pay down government debt, the sources said.  Japan s social welfare system is weighted toward spending on the elderly, with people aged 65 and over accounting for a whopping 27.7 percent of the population according to the latest government data.   You can promise anything you want - make a nod toward a more equitable society, empowering women, work-life balance, welfare for all generations,  said Jeffrey Kingston, director of Asian studies at Temple University Japan.  He s got a strategy that is going to win.  Using less tax revenue to pay down debt, however, would make more difficult an already ambitious pledge to balance the budget - excluding debt-servicing and new bond sales - by the year through March 2021. That could in turn raise concerns about less rigid fiscal discipline.  We have to maintain fiscal discipline, regardless,  Finance Minister Taro Aso told reporters when asked about reports of such a shift. Abe has said he will decide on a snap election after he returns from the United States on Friday. The opposition Democrats are struggling not only with single-digit support but also a raft of defections. And while the nascent  Japan First  party, which boasts ties to popular Tokyo Governor Yuriko Koike, could attract votes, it has yet to draft a platform, pick candidates or formally register as a party. That means the LDP and its junior coalition partner, the Komeito, have a shot at retaining their two-thirds majority in the lower house, political analysts said. However, some analysts believe Abe s electoral base could be undermined by voter distaste over suspected cronyism scandals and concerns about creating a political vacuum even as North Korea raises tensions with its nuclear and missile tests.  I don t dismiss the possibility of the voters giving Abe a nasty surprise,  said Gerry Curtis, professor emeritus at Columbia University in New York. 