A trip to London provides an occasion to compare and contrast British politics and attitudes with those in America.

Both have, in different ways, divided government. The Democratic president has been frustrated by the Republican House of Representatives and is likely but not certain to be until January 2017.

Britain's ruling coalition has been occasionally strained by disagreements between the dominant Conservatives and the junior Liberal Democrats but seems likely to survive until the general election scheduled for May 2015.

In America the big-spending policies of the Obama administration have been followed by sluggish economic growth, persistently high unemployment and low workforce participation.

The British coalition's cuts in what Americans call discretionary spending have been followed by roughly zero economic growth but relatively low unemployment and relatively high workforce participation.

In neither country is any party confident of winning the next presidential or general election. In both countries, young voters may be critical in determining who wins.

Young voters in both countries hold libertarian views on cultural issues. They tend to favor same-sex marriage and legalized marijuana, while the elderly tend to be strongly opposed. But there is an apparent difference on economic issues.

Americans under 30 tend to support big government policies more than their elders. They're likely to tell pollsters that government should do more to solve problems -- a position rejected by most American voters over the last 30 years.

This Millennial Generation was also far more likely to support Barack Obama, who won 66 percent of their votes in 2008 and 60 percent in 2012. Obama carried older voters by only 1 percent in 2008 and lost them to Mitt Romney in 2012.

Young Brits seem to take a different view. In British Social Attitudes surveys, they reject the policy of government-paid residential care for the elderly and express approval for big companies.

They were born into a Britain where Margaret Thatcher's Conservatives privatized state industries and sold public housing units to tenants. They evidently dislike paying high taxes to support the currently scandal-plagued National Health Services ("ring-fenced" or spared from spending cuts, by the coalition government).

And they seem to heartily support the coalition's cuts in welfare spending. They may have a hard time finding jobs, and they resent those who are sponging off the government for life.

Conservatives have hopes of winning more Millennial votes in 2015. The most popular political figure among the young is London's Conservative and libertarian Mayor Boris Johnson.

And the coalition government has pushed legalization of same-sex marriage through both houses of Parliament. Prime Minister David Cameron speaks passionately on the subject.

This has caused some backlash among older Conservative Party members and voters. It may explain why the United Kingdom Independence Party, known mainly for its opposition to British membership in the European Union, has been showing increased strength in recent polls and local elections.

Are there lessons here for America's Republicans, who some say are doomed because of high support for Barack Obama among Hispanics and (the twice as numerous) Millennials?

Perhaps. The proprietors of Obamacare are sounding panicked about the possibility that many Millennials will not sign up for insurance on the health exchanges.

The reason for panic is that health insurance won't be a good deal for the young. Obamacare requires that the relatively poor young pay for the greater medical needs of the relatively rich old.

The penalty for remaining uninsured is tiny compared to the cost of insurance premiums. And Obamacare guarantees that you can buy health insurance when you get sick or pregnant.

Obama's percentage among young voters slipped more than among their elders between 2008 and 2012. Some recent polling shows him with lower than average approval -- well under 50 percent -- among Millennials.

Republicans face problems with the young on cultural issues. Most Republican officeholders and voters oppose same-sex marriage.

But at least for a time, that issue was removed from national politics and sent to the states by two Supreme Court decisions.

Legalizing same-sex marriage in many states will require referendums. That tends to make the issue far less partisan. If Republicans want to appeal to Millennials, they should frame this as a matter of conscience, not politics, and show respect for the strong feelings on both sides.

Young Americans, like young Brits, want to choose their future. Republicans should argue their policies enable them to do so.