WASHINGTON — Seeking a successful health-care sign-up period despite troubling new challenges to his namesake law, President Barack Obama wants to make sure people start enrolling on Nov. 1. That’s when the window opens for choosing 2017 plans under the Affordable Care Act.

Obama planned to make that pitch during an appearance today at Miami Dade College in Miami. The White House said he’ll also tout improvements to the U.S. health care system under the 5-year-old law. But Obama will be attempting a difficult sales job.

Premiums are rising by double digits and some major insurers have pulled out of the program, leaving consumers with fewer choices next year.

Meanwhile, Health and Human Services Secretary Sylvia Burwell said this week that she expected 13.8 million people will sign up for 2017 coverage, a modest increase over the 12.7 million consumers who picked health insurance plans during open enrollment for this year.

White House spokesman Josh Earnest said Obama has laid out ideas for “tweaks” he thinks would improve the law, including allowing for a public option to increase competition. Under the public option scenario, the government would create and run a health insurance agency to compete with other private health insurance companies in the U.S.

But any changes would have to await the new Congress that gets seated in January, Earnest said. “The current Congress is one that’s dominated by Republicans who have voted more than 50 times to repeal the law, but have not once in the last six years actually put forward their own alternative proposal,” he said

The administration says taxpayer-provided subsidies that were designed to increase alongside premiums will soften most of the blow to people’s wallets from higher premiums. About 85 percent of customers get this kind of financial help. For policyholders who lost their insurers, the government will automatically match them to another carrier’s plan.

Still, millions of people buy individual policies outside of the health care law’s marketplaces and many of them will be hit with the full premium increases. Congressional budget analysts estimate there are about 9 million people nationwide with individual policies purchased outside the health care law. The administration estimates that about 5 million are eligible to buy coverage under the law, and half of those have incomes that would qualify them for subsidies.