In 2001, Senate Majority Leader Trent Lott got a dozen Democrats to vote for tax cuts sought by President George W. Bush.

Now, for the tax plan backed by President Trump, the most Democratic votes Sen. Mitch McConnell could hope for is three.

That count is shaping the Senate majority leader's strategy of going it alone on tax reform, planning to advance it through the reconciliation procedure that could allow a major tax bill to pass with only 51 Republican votes.

The state of affairs is attributable partly to the Democratic Party moving left on taxes as the Republican Party has moved right, as well as the greater influence of liberal Sens. Bernie Sanders and Elizabeth Warren.

But it's also a reflection of the total-war approach that Democrats have taken against the Trump administration, similar to the one that McConnell used in opposing former President Barack Obama when he declared that his aim was to make Obama a one-term president, said Robert Goulder, senior tax policy counsel with Tax Analysts.

"I think the Democratic Party, as it stands right now is very reluctant ... to give the Republicans a victory," Goulder said.

All but three Senate Democrats at the beginning of August pledged to oppose tax legislation that would produce tax cuts for the top 1 percent, a stipulation that likely would rule out the Republican effort to lower rates across the board.

Based on the letter, only Sens. Joe Donnelly of Indiana, Heidi Heitkamp of North Dakota, and Joe Manchin of West Virginia would be targets for "yes" votes. Those three relatively centrist lawmakers were also the only Democrats to vote to install Neil Gorsuch on the Supreme Court.

Just as it was more difficult for Trump to get Democratic support for his Supreme Court nominee than it was for President Ronald Reagan, so too will tax reform be more difficult than the bipartisan efforts in 1986 and in 2001. The White House has reportedly reached out to Democrats to gauge support.

"I don't think this is going to be 1986, when you had a bipartisan effort to scrub the code," McConnell said before leaving Washington for Congress' August recess.

"It's a different world than it was 10 or 15 years ago," Senate Minority Leader Charles Schumer of New York told CNN Thursday. "The idea that people will support huge tax cuts for the rich when they're given a crumb won't work anymore."

The New York Democrat joined an effort with Republicans in 2015 to address the most pressing problem with the tax code, the trillions of dollars' worth of corporate earnings held overseas untaxed, and the pressure on U.S. companies to move their headquarters to tax havens. At that time, Obama said his goal was to lower the corporate tax rate from 35 percent to 28 percent.

Obama's effort at bipartisan tax reform failed, largely because Republicans and their small-business constituents wanted lower individual rates to go along with a reduced corporate rate.

But after Sanders' strong showing in the Democratic Party's presidential campaign, there may be less enthusiasm in the party for unlocking the trillions of dollars trapped overseas or reforming the way the U.S. taxes international profits.

"I think when you look at sort of the more progressive part of the Democratic Party, the sort of Bernie Sanders party, they don't think you should give any preference to foreign profits," Goulder said.

On the campaign trail, the independent Vermont senator called for ending the practice of allowing companies to "defer" taxation on foreign profits as long as those earnings are not brought back into the U.S. That policy has resulted in businesses holding an estimated $2.6 trillion overseas.

Whereas Republicans are seeking to lower corporate rates and end taxation of foreign profits altogether, Sanders would have gone in the other direction, taxing them immediately on their overseas profits at the full 35 percent rate.

Although Sanders is to the left of most of the Democratic caucus, he may have shifted the center.

Massachusetts' Warren called this year for raising corporate taxes, rather than lowering them, telling Yahoo that companies should pay a greater share of the government's revenue.

"There's been more and more awareness that actually C-corporations are not paying 35 percent in taxes," said Steven Wamhoff, a tax expert at the Institute on Taxation and Economic Policy, a left-of-center think tank. His group has highlighted that corporations as a group pay much lower than 35 percent of their profits in taxes, thanks to the deductions and credits available to them.

For more centrist Democrats who might be inclined to find a deal, the Republican Party's pursuit of a 15 percent or 20 percent corporate tax rate with lower individual rates is a tough ask.

Sen. Mark Warner, D-Va., noted at a recent hearing that in 2010, the bipartisan Bowles-Simpson deficit-reduction commission suggested lowering corporate rates as low as 26 percent. Since then, however, Republicans have lowered the target rate, partly because other countries have lowered theirs. The "bid and the ask" between the two parties has accordingly widened, Warner said.

"America actually ranks as one of the lowest-taxed industrial nations in the world," he said.