The Senate voted Wednesday to open debate on a $1.4 trillion tax bill after Republican leaders worked out preliminary deals to the smooth over the concerns of several Republican lawmakers.

The final tally was 52-48, passing strictly along party lines. The vote means the bill is now open to debate and unlimited amendments, several of which are expected to win approval and become part of the base bill.

Debate began shortly after President Trump promoted the GOP tax reform plan in St. Charles, Missouri.

“As President Trump made clear today, fixing our broken tax code is about two things, helping hardworking Missouri families keep more of what they earn and ensuring there are more opportunities and better-paying jobs for every American,” Sen. Roy Blunt, R-Mo., said after the speech.

The base legislation lowers corporate and individual tax rates while ending many deductions. It also effectively repeals Obamacare’s mandate to purchase health insurance by eliminating the fine for not having coverage.

Senate Republicans hope to pass the bill this week.

House Republicans passed their own tax reform bill earlier this year and said Wednesday they plan to go to conference with the Senate to work out a compromise plan between the two chambers, rather than simply endorse the Senate plan.

“We’ll pick the best of the provisions when we go to conference,” House Ways and Means Committee Chairman Kevin Brady, R-Texas, who authored the House bill, told the Washington Examiner.

Final passage in the Senate is not yet assured. Several Republicans remain undecided, including Sens. John McCain and Jeff Flake, both of Arizona.

Sen. Bob Corker, R-Tenn., a staunch deficit hawk, said he is seeking a language that would raise taxes or impose spending cuts if the tax reductions that are part of the legislation lead to an increase in the deficit.

Sens. Ron Johnson, R-Wis., and Steve Daines, R-Mont., are seeking an expansion of tax cuts for small businesses in exchange for their support.

Some of the issues are expected to be resolved with amendments. Sen. Susan Collins, R-Maine, said she has filed a list of amendments, including one that would restore a deduction for state and local property taxes but install a $10,000 cap.

One would pay for the restoration of the property tax deduction by raising the proposed 20 percent corporate tax rate to 21 percent. Another would repeal for two years an Obamacare provision that raises the threshold for deducting catastrophic health expenses from 7.5 percent of income to 10 percent of income.

Collins said she will also introduce an amendment that would make the child and dependent tax credit refundable, paying for it with a repeal of the carried interest allowance. And another would restore the ability of public and non-profit employees to make catch-up contributions to their retirement accounts.

“Some of these are higher priorities than others,” Collins said.

Collins is among three Republicans who last summer refused to support a bill to repeal and replace Obamacare. But Republican leaders have so far been able to keep Collins on board with tax reform.

In this instance, they offered a healthcare sweetener, promising a vote by the end of the year on a a measure to add additional funding for Obamacare insurers to help cover the most expensive customers in an effort to lower premiums.

“We are working out the details of that,” Collins said.

No Democrats voted to begin debate and none are expected to support final passage. Democrats argued Wednesday the bill would explode the debt and provide only temporary tax relief to individuals while providing a large and permanent corporate tax cut.

“This is a disgraceful bait and switch,” said Sen. Michael Bennet, D-Colo.

Democrats contend they would have been willing to negotiate with Republicans but that the GOP cuts were too steep.

Sen. Tom Carper, D-Del., called the bill “an affront to fiscal responsibility.