Editor’s note: This story is part of an occasional Associated Press series examining the issues at stake in the presidential election between now and Election Day. Read more from “Why it matters.”
THE ISSUE:

Russia cannot be ignored. Since the end of the Cold War, Russia has never posed such a vexing problem to U.S. policymakers as it does now. From Eastern Europe to the Middle East and increasingly Asia and the Americas, Russia is making its voice heard and its presence felt.

After a brief period of looking inward during much of President Obama’s first term, Russia has returned to the international stage with zeal under Vladimir Putin. Russia is militarily involved in Syria, supports separatists in eastern Ukraine and areas of Georgia, and has even been accused of trying to meddle in the U.S. presidential race. At the same time, the Obama administration has been forced to accept that working with Russia is probably the only way to achieve results on many complicated international issues. Thus, Russia was central in the Iran nuclear negotiations and is a player as well as a negotiator in the Syria truce effort.

WHERE THEY STAND:

Republican Donald Trump advocates improved relations with Russia – “Wouldn’t it be nice if we actually got along with Russia?” has been a standard line in his campaign speeches – and has been strikingly complimentary of Putin’s strong leadership style, contrasting it favorably with that of Obama. Some of Trump’s current and former top advisers have been criticized for being too close to Putin, and Democrats have accused the businessman of pandering for Russian praise. Trump, however, is not the first politician to champion better U.S. ties with Russia.

In fact, one of Hillary Clinton’s first initiatives as secretary of state in 2009 was to “reset” relations with Moscow, an effort that produced decidedly mixed results.

The “reset” policy had some successes while Putin was taking a break from the Russian presidency. On Putin’s return, though, the reset began to unwind and Russia started to take positions directly opposed to the U.S., notably in support of President Bashar Assad in Syria and then in Ukraine. Clinton has had direct negotiating experience with Putin and his aides and that has left her wary of cooperating with Moscow. Her campaign says she will “stand up to Vladimir Putin,” “deter Russian aggression in Europe” and “increase the costs to Putin for his actions.”

WHY IT MATTERS:

Relations between the former Cold War foes – the owners of the most nuclear weapons on Earth – are arguably some of the most important to leaders in both the White House and Kremlin. Animosity or cordial friendship can bring profound changes in international affairs and the next president will have to engage or confront Russia on a variety of matters, not least of which are allegations that Russia may have been behind the hacks of Democratic National Committee emails.

The conflicts in Syria and Eastern Ukraine will not end without Russian buy-in, and Russia will have to be involved in any new effort to bring North Korea back to denuclearization talks. In the meantime, Russia is a driving force behind the co-called BRICS group of nations – Brazil, Russia, India, China and South Africa – that sees itself as a balance to the U.S. superpower and may also present problems for the U.S.