Ten years ago, voters stripped Republicans of their majorities in both the House and Senate. Two years later, Republicans lost the White House. Ever since that Democratic ascendance of 2006 and 2008, Republicans have been scrabbling to regain power in Washington. They vowed to American voters that this time, a return to the GOP's single-party governance would result in reform and real prosperity, not the international misadventures and domestic issues of the Bush years.

In 2016, Republicans finally got their wish. And in 2017, it's time to deliver.

The stakes for Republicans are high, and their initial action — an ill-conceived gutting of a congressional ethics watchdog that they quickly backtracked on — does not bode particularly well. The GOP needs to take governing seriously. Because a failure to deliver dramatic victories in the first few months of their historic control of Washington could spark even more discontent and disunity, and leave Republicans consumed by fierce in-fighting that will give a broken Democratic Party the tools it needs to heal.

Nowhere is that more true than with ObamaCare. After spending the last six years promising the repeal of ObamaCare — unrealistically, while Barack Obama remained president — the new Congress has the Affordable Care Act squarely in its sights. The House has passed dozens of repeals, but until the GOP took control of the Senate, those bills went nowhere. And even when both chambers finally managed to send a repeal bill to President Obama, he promptly and predictably vetoed it.

This time around, Republicans control both chambers with Donald Trump in the White House. At first, Republicans on Capitol Hill signaled that they may be getting cold feet over repeal, floating trial balloons about using a three-year process and suggesting that Trump's other priorities might take precedence. Trump eventually made his priorities clear by appointing leading ObamaCare critic Tom Price to head the Department of Health and Human Services, and leaders in both the House and Senate now say that a repeal through the reconciliation process will be their first legislative task.

Still, this might be a promise easier made than accomplished. Despite its passage through reconciliation (which only requires 51 votes in the Senate, thus preventing the need for a filibuster-proof 60-vote supermajority), ObamaCare has several components that do not easily fall into the budgetary-impact category to which reconciliation applies. That means some parts of the repeal will be subject to Democratic filibusters — as will proposals to replace ObamaCare with the free-market health insurance reform plan that Price and House Speaker Paul Ryan have. In the meantime, voters might have to endure several months of ambiguity between an immediate but partial repeal and the next open-enrollment period in November. If Republicans haven't succeeded in replacing ObamaCare by that time, voters will find the failure difficult to fathom after handing over full control of the federal government to the GOP.

Republicans will likely have an easier time on regulation, thanks in large part to Obama's go-it-alone strategy in his second term. Obama avoided Republicans in Congress — and let's be honest, they weren't eager to work with him either — preferring to use executive authority to achieve his goals. Trump's Cabinet picks will have that same significant latitude to roll back Obama's agenda, as well as fulfill the long-standing Republican pledge to eliminate intrusive and costly regulation. Trump's nominations of Price at HHS, former Texas Gov. Rick Perry at the Energy Department, and former Oklahoma Attorney General Scott Pruitt at EPA promise a rapid effort in scrapping regulations.

Then there's tax reform. This is another Republican agenda item on which voters have long waited for action — and might present another opportunity for disillusionment. Conservatives have argued for a flat tax in both the individual and corporate tax systems, while the consumption-targeted "Fair Tax" and repeal of the 16th Amendment has garnered more support from populists. Trump has not shown much interest in either solution, preferring to focus more on adapting the existing systems for his own benefit — and using it as a lever to wring concessions out of major employers. Republicans in Congress will be sorely tempted to keep the existing systems in place too, with the ability to replace Democratic social engineering with their own preferred version.

Until now, Republicans had a handy excuse for their inability to deliver: Barack Obama. But they overpromised in 2014 and touched off a populist revolt on the right that resulted in the nomination and election of Donald Trump. Overpromising and underdelivering has real-world consequences for political parties, even when the lack of success has rational explanations. Underdelivering in single-party governance could have catastrophic consequences for the GOP. The next several weeks will show whether they understand that.