HELSINKI — Standing side by side with Vladimir Putin, President Donald Trump refused Monday to blame the Russian leader for meddling in the 2016 U.S. presidential election, undercutting the nation’s intelligence community and handing the autocrat a diplomatic victory.Although he faced pressure from critics, allied countries and his own staff to take a tough line, Trump spoke not a single disparaging word in public about Moscow on any of the issues that have brought relations between the two powers to the lowest ebb since the Cold War.Instead, Trump denounced the “stupidity” of his own country’s policies, especially the decision to investigate Russian interference in the election.Just three days ago, the Justice Department announced an indictment of 12 Russian spies for hacking into Democratic Party computer networks.