WASHINGTON (Reuters) - Republicans in Congress are planning a light legislative agenda as they return from their long summer break on Tuesday, a strategy some say is designed in part to bog down Hillary Clinton if she becomes president.  It is not uncommon for the Congress to take it slow in an election year and legislative delays could work in Republicans’ favor if their nominee Donald Trump takes the White House in November. But the strategy will also pay dividends if it is Clinton who takes office on Jan. 20. She will be forced to deal with old baggage rather than focus on her agenda of infrastructure investments and immigration and Wall Street reforms. “If Hillary wins, we force her to waste time, resources, momentum, early good will and political capital - all on cleanup duty,” said a senior aide to one Republican senator. If all goes as expected this autumn, a U.S. Supreme Court seat, vacant since Feb. 13, will remain unfilled until sometime next year. A sweeping Pacific free-trade deal negotiated by President Barack Obama will be on hold, if not doomed. And if many conservative Republicans get their way, government agencies will run on stop-gap funding from Oct. 1 until sometime in February or March. That means that the next president would have to negotiate a longer-term deal or face the prospect of government shutdowns in the early days of a new administration. Senior congressional aides have told Reuters their agenda for the coming months include bills to keep the government funded, combat the spreading Zika virus and renewing laws guarding the nation’s water resources. Other items would help the majority Republicans score political points with key constituencies before the November elections, even though they have no chance of becoming law. These include scolding the Obama administration for a $400 million payment to Iran in January after Tehran released American prisoners, anti-abortion measures and, once again, proposals to repeal Obama’s landmark healthcare law. Ron Bonjean, a Republican strategist and former aide to Republican leaders in Congress, acknowledged that public opinion polling is trending in Clinton’s direction. If Clinton wins, Bonjean added, “The whole mindset (among Republican leaders in Congress) would shift to taking care of the most important business to help Republicans and unloading the more difficult, tense issues for a Clinton administration to deal with.” Clinton has maintained a lead in most polls since Republican and Democratic conventions, but some surveys showed that lead narrowing. A Reuters/Ipsos poll released on Sept. 2 showed Trump effectively pulling even with the Democratic nominee. Yet one veteran Republican congressional aide said more and more Republicans in Congress brace for the White House to stay in Democratic hands for the next four years, even if their party manages to maintain control of Congress. Trump’s trouble in appealing to important groups of voters, such as Hispanics, African-Americans and Asians, and self-inflicted wounds “have made it pretty clear he’s highly unlikely to get there,” he said. Leaving the Supreme Court nomination and other high-profile disagreements for 2017 “does bog down” a new administration, “no question about it,” the aide said. Some election years mean a slow autumn in Congress, but this is not always the case. In 2012 for example, lawmakers dramatically labored all the way through New Year’s Eve addressing a “fiscal cliff” of expiring tax and spending laws.  Not all of the delays in passing legislation are purely on Republican shoulders though. While Trump has blasted free-trade deals, leading Democrats, including Clinton, also have criticized Obama’s Trans-Pacific Partnership pact that would create a free-trade zone ranging from Japan to Chile. Stephen Hess, a senior fellow at the Brookings Institution, downplayed the challenges Clinton might face early on. “She knows how to deal with Congress. She’s been there,” he said referring to Clinton’s years as a senator representing New York. Besides, he added, if Trump loses, Republicans will be busy dealing with their own problems.  “They’ll have to think seriously about how they got themselves in the trouble that they’re in.” 